A BIO-based coating for agricultural applications.

Abstract

The present invention relates to a bio-based coating for agricultural applications. The present invention further relates to a particle, in particular a fertilizer or a plant seed, comprising the bio-based coating, to a method for manufacturing the bio-based coating, to the coated particle obtained by the method, and to methods of sealing cracks, voids or imperfections of a coating on a solid particle and controlling a release rate of nutrients from a solid fertilizer.

Description

[0001] A BIO-BASED COATING FOR AGRICULTURAL APPLICATIONS.

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a bio-based coating for agricultural applications. The present invention further relates to a particle, in particular a fertilizer or a plant seed, comprising the bio-based coating, to a method for manufacturing the bio-based coating, to the coated particle obtained by the method, and to methods of sealing cracks, voids or imperfections of a coating on a solid particle and controlling a release rate of nutrients from a solid fertilizer.

[0004] RELATED APPLICATIONS

[0005] The present application claims the benefit of priority from Dutch Patent Application NL2036585, filed on December 19, 2023, in the name of Technische Universiteit Delft, The Netherlands.

[0006] The entire contents of the above-referenced applications and of all priority documents referenced in the Application Data Sheet filed herewith are hereby incorporated by reference for all purposes.

[0007] BACKGROUND OF THE INVENTION

[0008] In the field of coated agricultural products, such as fertilizers and plant growth and protection products, it is common to apply both synthetic and natural polymers for encapsulation. Fertilizers undergo coating with a (mixture of) organic and inorganic materials to achieve delayed nutrient release, synchronizing the supply with plant's nutritional requirements. Additionally, solid fertilizers are coated or encapsulated to prevent rapid nutrient release, thereby mitigating issues like leaching, volatilization of greenhouse gases, surface runoff, and plant burning. Such coated fertilizers exhibit slow and / or controlled nutrient release, dependent on the level of control over the rate, pattern, and duration of sustained release. For instance, polymer-coated urea, utilizing polyesters, polyurethanes, polyacrylamides, polystyrene, polydimethylsiloxane, polysulfones, and the like, serves as an example of a controlled release fertilizer. Delayed fertilizer release offers numerous advantages, including higher nutrient usage efficiency, reduced environmental nutrient loss, prevention of nutrient fixation to soil, and improved soil fertility and crop yield at lower nutrient application rates. Furthermore, controlled release fertilizers have proven effective in reducing fertilizer usage by 20 to 40%, or even higher, up to 80%, of the recommended rate while maintaining comparable crop yields. In some cases, polymeric coatings contribute to beneficial soil water retention, cementing their status as environmentally friendly and climate-smart agricultural practices.

[0009] Various methods exist to delay nutrient uptake following application, such as employing a polymeric membrane with lowered water permeability, a polymeric membrane permitting diffusion solely through erosion, or polymer technology based on polymer / nutri- ent microbial degradation. The ideal release time of a coated fertilizer is designed to align with a plant or crop's nutritional demands. To facilitate plant growth, seeds can also be protected from the environment through film dressing and polymeric coatings. Seed coatings primarily aim to deliver an array of active components directly onto the seeds to ensure successful germination, encompassing nutrients, pesticides, microbes, and even colorants for identification purposes. A relevant aspect of seed coating technology revolves around superabsorbent encapsulation materials, where the coating imparts an increased water retention capacity, fostering germination, plant growth, and biodegradability. The polymeric seed coating elevates the germination success rate and acts protectively, enhancing shelf life.

[0010] Clear disadvantages of coatings as described above are that such coating formulations predominantly comprise synthetic non-biodegradable polymers. Disadvantages of such ingredients are further emphasized as for example through European goals towards sustainable food production encompassing the replacement of fossil-based plastics. Agricultural plastics have long been recognized as an environmental threat, particularly due to their fragmentation into microplastics (< 5 mm). Consequently, synthetic polymer-coated crop protectants, such as microcapsules, coatings, and mulching films, face imminent phase-out by regulatory bodies. Notably, the EU Commission proposed restrictions in 2015 (according to Annex XIII of REACH) to control some intentionally added microplastics, including those used in agrichemical and seed coatings, by 2021. For controlled-release fertilizers, even more ambitious plans are relevant in view of the EU Fertilizing Products Regulation which sets forth a biodegradability criterion starting in 2026. Further (national) incentives are the transition from fossil-based plastics in agriculture, in The Netherlands, and The "Nederland Circular in 2050" national program, aligning circular economy objectives with the agricultural sector. Measures include substituting plastic raw materials with circular biobased products, derived wholly or partially from biomass and residual streams. Moreover, significant attention has been devoted to addressing excessive nitrogen deposition and emissions from agriculture, primarily emanating from manure and stringent targets are set by to reduce emissions by half before 2030. In this endeavour, the appropriate use of nitrogen fertilizers based on type, application, and release specifications thus proves to be invaluable. Therefore, despite the great advances made in technology development of coated fertilizers and plant growth and protection products, the whole area of biodegradability and sustainability still needs to be further addressed.

[0011] Incidentally reference can be made to WO 2020 / 096454 Al, US 2018 / 258005 Al, WO 2020 / 044189 Al, WO 2022 / 076877 Al and WO 2024 / 003455 Al. WO 2020 / 096454 Al recites a controlled-release device for horticulture such as a plant pot, rod, stick, tablet, coating or the like, said device comprising a biodegradable composition comprising a bioactive component and a biodegradable matrix, wherein the biodegradable matrix comprises a natural polymer (e.g. a polymeric carbohydrate) and a biopolyester, and a method for preparing the biodegradable controlled-release device. US 2018 / 258005 Al recites a coating matrix operable for coating fertilizer particles. The coating matrix is made from a whole biomass composition, in which said whole biomass composition comprises at least a microalgae and a macroalgae reduced to a powder form, mixed with an aqueous solution of alkali metal hydroxide or alkaline earth metal hydroxide at a concentration ranging from 0.1% to 20% (w / v). The mixture is mixed at about 7 pH to about 9.5 pH which produces a cross-linked polysaccharide. WO 2020 / 044189 Al recites a seaweed and / or seaweed extract coated fertilizer core, methods for their use, and production thereof, are disclosed. The fertilizer core, coated by the seaweed and / or seaweed coating, can contain 50 wt. % or more, based on the total weight of the core, of a urea-based fertilizer, or an inorganic fertilizer containing one or more of nitrogen, phosphorus, or potassium, or a combination thereof. The coating can include a seaweed and / or seaweed extract, and optionally contain or exclude gypsum, water insoluble polymer(s) other than native water insoluble polymers present in the seaweed or extract thereof, water, solubilizing agent(s), anticaking agent(s), and / or binding agent(s). WO 2022 / 076877 Al recites biodegradable, bioactive biopolymer nanocoating platforms, compositions thereof, and methods for making and producing the biopolymer nanocoating platforms. The present disclosure also provides various agricultural applications of the biodegradable, bioactive biopolymer nanocoating platforms. WO 2024 / 003455 Al recites a controlled release coated fertilizer product comprising a fertilizer granule core and a coating of readily biodegradable components and natural polymers. The coating comprises an inner layer comprising lignin and a hydrophobic outward layer. The present disclosure further concerns a method for preparing a coated fertilizer product and the use of the coated fertilizer for controlled release of nutrients in farming.

[0012] The present inventors developed a coating, aiming at a coating which is fully biodegradable and sourced sustainably. The present invention therefore relates to a bio-based coating, for agricultural application, further aspects thereof, as well as a method of fabricating the bio-based coating, which overcomes one or more of the above disadvantages, without compromising functionality and performance.

[0013] SUMMARY OF THE INVENTION

[0014] It is an object of the invention to overcome one or more limitation of the coatings of the prior art and at the very least to provide an alternative thereto. The present exemplary bio-based water-soluble coating provides a fully biodegradable and sustainable coating, which surprisingly was found to be super-waterabsorbent with a remarkably high water retention capacity with a high swelling effect; the innovative swelling effect of the coating holds significant value, as it can seal cracks and prolong the nutrient diffusion path, enabling delayed release through a hydrogel barrier. The present coating surprisingly provides a coverage of an underlying material, in use, from the outset of nearly 100 surface %, such as 98- 1000 surface %. If any open area remains present, said open area is fully covered in use. The coating is substantially homogeneous over a surface of the coating. The present coating also provides an improved storage stability of the coated particle, such as > 6 weeks. In a first aspect, the invention relates to a particle (3), comprising a bio-based water-soluble coating, in particular for agricultural application, the bio-based coating comprising at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, comprising (la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and (lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, and (1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer, wherein the particle is encapsulated by the bio-based coating, and wherein the at least one first layer is provided on the outer surface of the particle. The term “water- swellable” relates to the water-absorbent typically hydrophilic polymer, such as a homopolymer or a copolymer, that can absorb and retain extremely large amounts of a liquid relative to its own mass. Volume-wise the amount of absorbed water may easily exceed 10 times the volume of the polymer itself, whereas ratios of 50-100 are easily obtained with the present water-swellable coating. The water-swellability, and likewise the super absorbent capacity, is typically quantified by a swelling ratio; for the present coating the swelling ratio is at least 2 (vol. / vol.), and typically at least 5. The term “water-retention capacity” clarifies that the present water-soluble coating is capable of retaining significant amounts of water, both in terms of relative weight amounts (g / g) and in terms of relative volume amounts (vol. / vol.), as above for the water-swellability. The relative increase in weight can easily be measured with a laboratory balance, such as a Mettler Toledo Balance XPR204S / M. The relative increase in volume can easily be measured with an ElastoSens™ Bio, which effectively relates to adding the to be measured material in a holder, adding water, and measuring a difference between final and initial volume. The term “water-based” relates to a capability of the present coating, or its constituents, to dissolve in water, that is , dissolve to an extent of >80 wt.% thereof, typically > 90 wt.% thereof. The present coating, and in particular the polymers thereof, are therefore considered to be water-soluble. The term “encapsulated by the bio-based coating” as used herein also encompasses “substantially encapsulated by the biobased coating”. The term substantially as used herein, will be understood by the person skilled in the art, and may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. In general, the term substantially may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. In particular related to the present invention the term substantially encapsulated as used in “substantially encapsulated by the bio-based water-soluble coating”, the outer surface of the particle is encapsulated for 90% or higher, such as 95% or higher, or 99% or higher, or 99,5% or higher, including 100%. The term non-polar binder as used herein refers to a binder with no polarity or substantially no polarity, or to a binder being hydrophobic or sufficiently hydrophobic. The nonpolar binder as used herein typically has a net dipole moment between 0 and 3 Debye (D), in particular between 0 and 2 D, more in particular between 0 and 1 D, more in particular between 0 and 0,5 D, more in particular between 0 and 0.1 D, and more in particular between 0 and 0.05 D. The non-polar binder is preferably an oil-based binder, in particular a non- impregnating oil-based binder, preferably a non-impregnating oil-based binder comprising at least one triglyceride, in particular a mixture of triglycerides, more preferably the non-impregnating oil-based binder is selected from at least one vegetable oil. The term “protective layer” as used herein refers to a layer, being an at least one first layer of the bio-based water- soluble coating, which is protective in view of the coated material, such as a granule or biologic material, such as a seed or fertilizer, thereby protecting the coated material from the outer environment. The environment may be any environment wherein said material may be located, such as air, or on soil, or in soil. Such environment can in practice have any circumstance you can think of, such as certain level of humidity, temperature, composition, etc. In order to protect a to be coated material, an at least first layer is added being a protective layer. The protective layer also concerns to be a uniform layer, wherein uniform refers to a layer wherein the components are all in a same phase, with a uniform distribution of the different component.

[0015] The term bio-based as used herein, refers to a material which is intentionally made from substances derived from living organisms, or from once-living organisms. Such materials are derived from materials of biological origin. Bio-based materials are often biodegradable, however, that is not always the case.

[0016] The term biopolymer as used herein refers to natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, classified according to the monomers used and the structure of the biopolymer formed: polynucleotides, polypeptides, and polysaccharides. Preferably, the biopolymers are biodegradable, more preferably the biopolymers are biodegradable and water-swellable.

[0017] The term plasticizer as used herein refers to a substance that is added to a material to make it softer and more flexible, to increase its plasticity. In the present invention the plasticizer is in particular selected from at least one of di-alcohol, di-alkanol, poly-alcohol, polyalkanol, carboxylic acid, carboxylic acid ester, amide, phosphate, and epoxide. It is noted that the skilled person will understand that a lubricant is functionally not the same as the present plasticizer. A lubricant helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. Lubricants are typically present t a surface, such as at the surface of rolling elements in a bearing. In addition to industrial applications, lubricants can be used for many other purposes. Other uses include a variety of applications, of which none has anything to do with increasing plasticity. It is mainly used to reduce friction and to contribute to a better, more efficient functioning of a mechanism. The skilled person would not confuse the two. Further, the term “dispersant” relates to a substance, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid to improve the separation of the particles and to prevent their settling or clumping. Dispersants are widely used to stabilize various industrial and artisanal products, such as paints, ferrofluids, and salad dressings. The plasticizers or superplasticizers, used to improve the workability of pastes like concrete and clay, are typically dispersants. The term “binder” is considered to relate to a material or substance that holds or draws other materials together to form a cohesive whole mechanically, chemically, by adhesion or cohesion. More narrowly, binders are liquid or dough-like substances that harden by a chemical or physical process and bind fibres, filler powder and other particles added into it. Examples include glue, adhesive and thickening. It is noted that the skilled person will understand that a binder is functionally not the same as the present plasticizer, nor a “dispersant”, and in fact are somewhat opposite. Plasticizers, binders, and dispersants are typically incorporated in a material. In summary: A plasticizer is typically a small molecule, usually non-volatile, that is at least partially miscible to the polymer system and results in decrease of the polymer system glass transition temperature. The molecule induces plasticization if the glass transition temperature is lowered by its addition to the system and alters the main polymer backbone mobility. An effective plasticizer molecule will sit in between the amorphous polymer chains (free volume). A good plasticizer remains in the product after mixing and processing. The concept of a plasticizer does not necessarily alter the plastic permanent deformation under load of the polymer system (plasticity). A lubricant is usually used during processing to alter viscosity (also termed rheology modifier) and / or reduce friction between an interface boundary or surfaces. A lubricant is not added to intentionally modify a final solid-state material property. Typically not a small molecule and not largely miscible to the polymer system. Lubricants can be rheology modifiers or additives if used to alter viscosity or enhance flow behaviour curve (e.g. can alter flow plasticity). Lubricants can also be used to reduce adhesion and friction (therefore also heat) by changing forces at interfacial layer / surface. A binder in a multicomponent mixture, will ensure its consolidation by bonding forces. The binder will improve the balance of adhesive and cohesive forces (bonds) to integrate the components of the mixture to a whole (at least to a macroscopic level). And a dispersant is typically a dispersant is a surfactant used to prevent flocculation and improve separation of particles, settling, precipitation, aggregation, or work as a wetting agent (improve substance coverage of a solid or substrate).

[0018] In a second aspect the present invention relates to a bio-based water-soluble coating comprising at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, comprising (la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and (lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, and (1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer.

[0019] In a further aspect the present invention relates to a method for manufacturing a coated particle comprising a bio-based water-soluble coating, in particular for agricultural application, the method comprising - providing a particle in a container, and in the container exposing the particle to (lb) at least one non-polar binder and optionally to (1c) at least one plasticizer, - adding to the container a powder comprising (la) at least one first biopolymer, thereby obtaining the coated particle, the coated particle comprising a particle encapsulated by a bio-based water-soluble coating, wherein the bio-based water-soluble coating comprises at least one first layer (1), the at least one first layer (1) comprising (la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and (lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, and (1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer.

[0020] In a further aspect the present invention relates to a coated particle obtained by the method as taught herein, in particular wherein the coated particle is a controlled-release particle, more in particular a controlled-release fertilizer.

[0021] In a further aspect the present invention relates to a method of sealing cracks, voids or imperfections of a coating on a solid particle, comprising applying the method as taught herein to the particle, thereby providing the bio-based water-soluble coating to the outer surface of the solid particle.

[0022] The term sealing cracks as used herein refers to the ability of the present coating to swell in the presence of water and thereby sealing cracks, voids or imperfections of a coating on the particle that exist or that appear along the way. Within the field of fertilizers, the innovative swelling effect of the coating holds significant value.

[0023] In a further aspect the present invention relates to a method of controlling a release rate of nutrients from a solid fertilizer, comprising applying the method as taught herein to the solid fertilizer, thereby providing the bio-based water-soluble coating to the outer surface of the solid fertilizer.

[0024] The term controlling release rate as used herein refers to affecting the rate of release of nutrients from a solid fertilizer. Such rate may be too fast, which results in a too high level of nutrients in the soil that will not be used by plants for which such nutrients are intended for. Under the assumption that the particle is fully coated, by addition of a hydrogel barrier to a particle, the nutrient diffusion path will be extended between the fertilizer and the soil and it will therefore take more time to release the said nutrients. Prolonging the nutrient diffusion path will thus enable a delayed release through a hydrogel barrier. Particularly noteworthy is the controlled super-absorbing behaviour achievable through layering. By adding more layers, depending on the particular or specific need, the release rate of nutrients can be controlled and thus be affected or delayed.

[0025] The coatings as taught herein display remarkably high water retention and are considered super-absorbent, with a mass uptake on initial weight. Within the field of fertilizers, this innovative swelling effect of the coating holds significant value, as it can seal cracks and prolong the nutrient diffusion path, enabling delayed release through a hydrogel barrier. The coating's ability to seal minor cracks while being super-absorbent represents an innovation in agricultural coatings. Particularly noteworthy is the controlled super-absorbing behaviour achievable through layering. The novel combination of controlled water retention and biodegradability of seed coatings highly desirable for promoting seed germination and soil health. Analogously, formulations employing this encapsulation strategy and biobased components can be developed. For example, plant, animal and microbial-based hydrogels.

[0026] The present invention provides a solution to one or more of the above mentioned problems and overcomes drawbacks of the prior art.

[0027] DETAILED DESCRIPTION OF THE INVENTION

[0028] In an exemplary embodiment of the present particle, the bio-based water-soluble coating is bio-degradable. The term bio-based as used herein, refers to a material which is intentionally made from substances derived from living organisms, or from once-living organisms. Such materials are derived from materials of biological origin. Bio-based materials are often biodegradable, however, that is not always the case. Bio-degradable as used herein refers to the breakdown of the bio-based material by microorganisms, such as bacteria and / or fungi. It is generally assumed to be a natural process. The process of biodegradation in general is threefold: firstly an object undergoes biodeterioration, which is the mechanical weakening of its structure; this is followed by bio-fragmentation, which is the breakdown of materials by microorganisms; and finally assimilation, which means that old material can be incorporated into new cells.

[0029] In an exemplary embodiment of the present particle, the bio-based water-soluble coating comprises at least one browning reaction product, in particular at least one non-enzy- matic browning reaction product, more in particular wherein the non-enzymatic browning reaction product is selected from a product of a chemical reaction between sugars and from a product of a chemical reaction between an amino acid and a sugar, more in particular at least one of a Maillard-reaction product and a caramelization-reaction product. Such a Maillard reaction may be regarded as provision of crosslinking to the present coating.

[0030] The term browning reaction product as used herein refers to a product resulting from a browning reaction. Browning is the process of material, such as for example food, turning brown due to chemical reactions that take place within. Browning falls in particular into two main categories: enzymatic and non-enzymatic browning processes. The browning reaction products of the present invention in particular relate to non-enzymatic browning reactions. Such browning reactions relate to a process without the activity of enzymes. Preferably such non-enzymatic browning reaction product is selected from a product of a chemical reaction between sugars and from a product of a chemical reaction between an amino acid and a sugar. Said chemical reaction between sugars relate to processes which involve the pyrolysis of sugar. An example of this process is known from cooking wherein it is used for the nutty flavour and brown colour, in particular known as caramelization as it produces a characteristic caramel flavour by its caramelization-reaction products. Said chemical reaction between an amino acid and a sugar relate to processes which involve a chemical reaction that takes place between the amine group of an amino acid and a carbonyl group of a sugar. The sugar interacts with the amino acid, producing a variety of odours and flavours. An example of this process and its related products is in particular known as Maillard-reaction and its Maillardreaction products.

[0031] In an exemplary embodiment of the present particle, the at least one first layer of the at least one layer is a hermetic layer.

[0032] In an exemplary embodiment of the present particle, the bio-based water-soluble coating is water-swellable.

[0033] In an exemplary embodiment of the present particle, the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer. The term “crosslinked” refers to providing a bond or a short sequence of bonds that links one polymer chain or part thereof to another polymer or another part thereof. These links may take the form of covalent bonds or ionic bonds. Covalent bonds would typically be referred to as “chemical” bonds, providing chemical crosslinking, whereas ionic bonds would typically be referred to a “physical” bonds, providing physical crosslinking. The present at least one first biopolymer is typically cross-linked chemically and or physically, typically chemically and physically. The polymers can be either synthetic polymers or natural polymers (such as proteins). In polymer chemistry "cross-linking" usually refers to the use of cross-links to promote a change in the polymers' physical properties.

[0034] In an exemplary embodiment of the present particle, the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g. Most conventional polymers might absorb some water; however they are also typically intended not to do so. The water swellability of such polymers, e.g. PE, PA, is therefore typically «10 mass / mass% (« 1.1 g / g), such as less than 5 %, or even les than 1 %(<1.01 g / g).

[0035] The term water-superabsorbent as used herein, refers to the properties of a layer comprising at least one biopolymer, wherein the biopolymer is a water-absorbing polymer that can absorb and retain extremely large amounts of liquid relative to its own mass. The term swelling ratio as used herein refers to the water-superabsorbent layer wherein for example 5g / g (grams per gram) means that the layer is able to swell 5 times its own weight; thus 1 gram of such layer can in case of 5g / g swell such that after swelling the layer’s weight is 5 g.

[0036] In an exemplary embodiment of the present particle, the bio-based water-soluble coating comprises 0-25 wt.% of a water-insoluble fibre, preferably 0-20 wt.%, more preferably 0-15 wt.%, most preferably 0-10 wt.%, in particular wherein the water-insoluble fibre is at least one of cellulose and a cellulose derivative.

[0037] In an exemplary embodiment of the present particle, the non-polar binder is an oilbased binder, in particular a non-impregnating oil-based binder, preferably a non-impregnating oil-based binder comprising at least one triglyceride, in particular a mixture of triglycerides, more preferably the non-impregnating oil-based binder is selected from at least one vegetable oil.

[0038] In an exemplary embodiment of the present particle, the first biopolymer is selected from at least one of a polynucleotide, a polypeptide and a polysaccharide, preferably the at least one first biopolymer is selected from at least one of animal-based biopolymers, plantbased biopolymers, and microbial-based biopolymers. Animal-based biopolymers can be selected from biopolymers such as at least one of chitosan, collagen, gelatine and casein. Plantbased biopolymers can be selected from biopolymers such as at least one of alginate, carrageenan and maize proteins. Microbial-based biopolymers can be selected from biopolymers such as at least one of gellan gum and biofilm-recovered polymers.

[0039] In an exemplary embodiment of the present particle, the at least one plasticizer is selected from at least one of di-alcohol, di-alkanol, poly-alcohol, poly-alkanol, carboxylic acid, carboxylic acid esters, amide, phosphate, and epoxide, in particular wherein the di-alcohol has a chain length of 2-24 carbon atoms, in particular 4-18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the di-alkanol has a chain length of 2-24 carbon atoms, in particular 4-18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the poly-alcohol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alkanol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alcohol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the poly-alkanol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the carboxylic acid has a chain length of 2-20 carbon atoms, in particular 4-16 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the carboxylic acid-ester has a chain length of 6-42 carbon atoms, in particular 8-38 carbon atoms, more in particular 10-34 carbon atoms. The term plasticizer as used herein refers to a substance that is added to a material to make it softer and more flexible, to increase its plasticity.

[0040] In an exemplary embodiment of the present particle, the bio-based water-soluble coating further comprises at least one additive, in particular wherein the at least one additive is selected from at least one of a polyphenolic additive and a cross-linker additive, in particular a cross-linker additive, more in particular a natural cross-linking compound, such as at least one of citric acid, oxalic acid, maleic acid, tartaric acid, folic acid, succinic acid, genipin, lignin, epigallocatechin gallate, catechin, procyanidin, oleuropein, proanthocyanidin, vanillin, and tannic acid.

[0041] In an exemplary embodiment of the present particle, the bio-based water-soluble coating further comprises at least one second layer (2), wherein the at least one second layer (2) is provided on the outer surface of the at least one first layer (1), wherein the at least one second layer is selected from at least one of a layer identical to the at least one first layer (1) and provided on the at least one first layer, and a layer different from the at least one first layer (1), and comprising a second biopolymer.

[0042] In an exemplary embodiment of the present particle, the layer different from the at least one first layer (1) is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g. The term swelling ratio as used herein refers to the water-superabsorbent layer wherein for example 5g / g (grams per gram) means that the layer is able to swell 5 times its own weight; thus 1 gram of such layer can in case of 5g / g swell such that after swelling the layer’s weight is 5 g.

[0043] In an exemplary embodiment of the present particle, the particle further comprises an additional layer of an anti-caking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, wherein the additional layer of anti-caking agent is provided on the outer surface of the outer layer. The term “anti-caking agent”, as used herein refers to a powder which is able to prevent particle aggregation or particle agglomeration. It reduces the ability of particles to stick to each other. It improves the usability and / or processability for the user of such particles comprising the said layer of anti-caking agent. In particular the anti-caking agents an excess of a third biopolymer.

[0044] In an exemplary embodiment of the present particle, the at least one first layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm.

[0045] In an exemplary embodiment of the present particle, the at least one first layer is a water-non-impregnating layer.

[0046] In an exemplary embodiment of the present particle, the at least one second layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm.

[0047] In an exemplary embodiment of the present particle, the at least one second layer is hydrophilic.

[0048] In an exemplary embodiment of the present particle, at least one layer selected from the at least one first layer and the at least one second layer is a gel-like layer, in particular a gel-like layer with a viscosity of > 1 Pa*s, in particular >10 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer. The viscosity value as used herein obviously cannot be an infinitely high value. Preferably, the gel-like layer has a viscosity value of < 200 Pa*s, in particular <150 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer.

[0049] In an exemplary embodiment of the present particle, at least one layer selected from the at least one first layer and the at least one second layer has a stiffness of Young’s modulus between 1 and 5 GPa, at a temperature of 20°C.

[0050] In an exemplary embodiment of the present particle, the particle is a solid particle selected from a pellet, a sphere, a granule and a biologic material, more in particular the solid particle is selected from a fertilizer, a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, more in particular selected from a fertilizer and a plant seed. The plant seed is preferably a seed of Spermatophyta, in particular at least one of Gym- nospermophyta, Pteridospermatophyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermophyta. The Gymnospermophyta is preferably selected from at least one of Cyadophyta, Ginkgophyta, Gnetophyta, Coniferophyta, and Cycadeoidophyta. The Pteridospermatophyta is preferably selected from at least one of Lyginopteridopsida, Medul- losopsida, Callistophytopsida, Peltaspermopsida, and Caytoniopsida. The Angiospermophyta is preferably selected from at least one of Monocotyledonae and Dicotyledonae . In particular the Angiospermophyta is selected from at least one of a cultivated crop plant and a flower plant.

[0051] In an exemplary embodiment of the present particle, the particle is a controlled release particle, in particular a controlled release fertilizer.

[0052] In an exemplary embodiment of the present particle, the bio-based water-soluble coating further comprises at least one component selected from nutrients, pesticides, microbes, and colorants.

[0053] In an exemplary embodiment of the present particle, at least one polymer selected from the first biopolymer and the second biopolymer is obtained from at least one of wastewater sludge and a wastewater treatment plant.

[0054] In an exemplary embodiment of the present particle, the at least one second biopolymer is at least one anionic polymer.

[0055] In an exemplary embodiment of the present particle, the bio-based water-soluble coating further comprises at least one cation, in particular at least one of ammonium, potassium, and sodium.

[0056] In an exemplary embodiment of the present particle, the particle is a controlled release particle, in particular a controlled release fertilizer.

[0057] In an exemplary embodiment of the present bio-based water-soluble coating, the biobased water-soluble coating is bio-degradable.

[0058] In an exemplary embodiment of the present bio-based water-soluble coating, the biobased water-soluble coating comprises at least one browning reaction product, in particular at least one non-enzymatic browning reaction product, more in particular wherein the non- enzymatic browning reaction product is selected from a product of a chemical reaction between sugars and from a product of a chemical reaction between an amino acid and a sugar, more in particular at least one of a Maillard-reaction product and a caramelization-reaction product.

[0059] In an exemplary embodiment of the present bio-based coating, the bio-based coating is water-swellable.

[0060] In an exemplary embodiment of the present bio-based coating, the bio-based coating comprises 0-25 wt.% of a water-insoluble fibre, preferably 0-20 wt.%, more preferably 0-15 wt.%, most preferably 0-10 wt.%, in particular wherein the water-insoluble fibre is at least one of cellulose and a cellulose derivative.

[0061] In an exemplary embodiment of the present bio-based coating, the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer.

[0062] In an exemplary embodiment of the present bio-based coating, the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g. The term swelling ratio as used herein refers to the water-superabsorbent layer wherein for example 5g / g (grams per gram) means that the layer is able to swell 5 times its own weight; thus 1 gram of such layer can in case of 5g / g swell such that after swelling the layer’s weight is 5 g.

[0063] In an exemplary embodiment of the present bio-based coating, the non-polar binder is an oil-based binder, in particular a non-impregnating oil-based binder, preferably a non-impregnating oil-based binder comprising at least one triglyceride, in particular a mixture of triglycerides, more preferably the non-impregnating oil-based binder is selected from at least one vegetable oil.

[0064] In an exemplary embodiment of the present bio-based coating, the at least one first biopolymer is selected from at least one of a polynucleotide, a polypeptide and a polysaccharide, preferably the at least one first biopolymer is selected from at least one of animal-based polymers, plant-based biopolymers, and microbial-based biopolymers.

[0065] In an exemplary embodiment of the present bio-based coating, the plasticizer is selected from at least one of di-alcohol, di-alkanol, poly-alcohol, poly-alkanol, carboxylic acid, carboxylic acid ester, amide, phosphate, and epoxide in particular wherein the di-alcohol has a chain length of 2-24 carbon atoms, in particular 4-18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the di-alkanol has a chain length of 2-24 carbon atoms, in particular 4-18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the poly-alcohol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alkanol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alcohol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the poly-alkanol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the carboxylic acid has a chain length of 2-20 carbon atoms, in particular 4-16 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the carboxylic acid-ester has a chain length of 6-42 carbon atoms, in particular 8-38 carbon atoms, more in particular 10-34 carbon atoms.

[0066] In an exemplary embodiment of the present bio-based coating, the bio-based coating further comprises at least one additive, in particular wherein the at least one additive is selected from at least one of a polyphenolic additive and a cross-linker additive, in particular a cross-linker additive, more in particular a natural cross-linking compound, such as at least one of citric acid, oxalic acid, maleic acid, tartaric acid, folic acid, succinic acid, genipin, lignin, epigallocatechin gallate, catechin, procyanidin, oleuropein, proanthocyanidin, vanillin, and tannic acid.

[0067] In an exemplary embodiment of the present bio-based coating, the bio-based coating further comprises an at least one second layer (2), wherein the at least one second layer (2) is provided on the outer surface of the at least one first layer (1), wherein the at least one second layer is selected from at least one of

[0068] - a layer identical to the at least one first layer (1) as taught herein, and

[0069] - a layer different from the at least one first layer (1), and comprising a second biopolymer, and wherein, if the at least one second layer comprises both the layer identical to the at least one first layer as well as the layer different from the at least one first layer, the layer identical to the at least one first layer is in between the at least one first layer and the layer different from the at least one first layer. In other words, in this particular embodiment the bio-based coating further comprises an at least one second layer (2) provided on the outer surface of the at least one first layer (1), wherein the at least one second layer is either a layer identical to the at least one first layer (1) as taught herein, or a layer different from the at least one first layer (1), and comprising a second biopolymer, or the at least one second layer is a combination of one or more of the said layers. In case of the at least one second layer is a combination of one or more of the said layers, the layer identical to the at least one first layer is in between the at least one first layer and the layer different from the at least one first layer.

[0070] In an exemplary embodiment of the present bio-based coating, the layer different from the at least one first layer (1) is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

[0071] In an exemplary embodiment of the present bio-based coating, the at least one first layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm.

[0072] In an exemplary embodiment of the present bio-based coating, the at least one first layer is a water-non-impregnating layer.

[0073] In an exemplary embodiment of the present bio-based coating, the at least one second layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm.

[0074] In an exemplary embodiment of the present bio-based coating, the at least one second layer is hydrophilic.

[0075] In an exemplary embodiment of the present bio-based coating, at least one layer selected from the at least one first layer and the at least one second layer is a gel-like layer, in particular a gel-like layer with a viscosity of > 1 Pa*s, in particular >10 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer. The viscosity value as used herein obviously cannot be a infinitely high value. Preferably, the gel-like layer has a viscosity value of < 200 Pa*s, in particular <150 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer.

[0076] In an exemplary embodiment of the present bio-based coating, at least one layer selected from the at least one first layer and the at least one second layer has a stiffness of Young’s modulus between 1 and 5 GPa, at a temperature of 20°C.

[0077] In an exemplary embodiment of the present bio-based coating, the bio-based coating further comprises an additional layer of an anti-caking agent, in particular an excess of a third biopolymer, wherein the additional layer of non-stick powder is provided on the outer surface of the outer layer. The term “anti-caking agent”, as used herein refers to a powder which is able to prevent particle aggregation or particle agglomeration, such as a non-stick powder, or an anti-stick powder. It reduces the ability of particles to stick to each other. It improves the usability and / or processability for the user of such particles comprising the said layer of anti-caking agent. In particular the anti-caking agents an excess of a third biopolymer.

[0078] In an exemplary embodiment of the present bio-based coating, at least one polymer selected from the first biopolymer and the second biopolymer is obtained from at least one of wastewater sludge and a wastewater treatment plant.

[0079] In an exemplary embodiment of the present bio-based coating, the at least one second biopolymer is at least one anionic polymer.

[0080] In an exemplary embodiment of the present bio-based coating, the bio-based coating further comprises at least one cation, in particular at least one of ammonium, potassium, and sodium.

[0081] In an exemplary embodiment of the present method, the method is repeated at least one time, thereby providing an at least one second layer on the outer surface of the at least one first layer, thereby obtaining a particle encapsulated by a bio-based coating comprising at least two layers, wherein both at least two layers comprise at least one non-polar binder, at least one first biopolymer, and optionally at least one plasticizer.

[0082] In an exemplary embodiment of the present method, an at least one further layer comprising a second biopolymer is provided on the outer surface of the coated particle, in particular by applying at least one of suspended biopolymers and aqueous-soluble biopolymers, in particular wherein the at least one further layer is a water-superabsorbent layer with a high water-retention capacity.

[0083] In an exemplary embodiment of the present method, a further layer of anti-caking agent is added, in particular an excess of a third biopolymer, wherein the additional layer of anti-caking agent is provided on the outer surface of the coated particle, for preventing coated particle aggregation. The term “anti-caking agent”, as used herein refers to a powder which is able to prevent particle aggregation or particle agglomeration. It reduces the ability of particles to stick to each other. It improves the usability and / or processability for the user of such particles comprising the said layer of anti -caking agent. In particular the anti-caking agent is an excess of a third biopolymer.

[0084] In an exemplary embodiment of the present method, the powder comprising at least one first biopolymer has a particle size distribution of 150 pm with a standard deviation of 50 pm.

[0085] In an exemplary embodiment of the present method, the coated particle is subjected to a browning reaction, in particular a non-enzymatic browning reaction, in particular a chemical reaction selected from a chemical reaction between sugars and a chemical reaction between an amino acid and a sugar.

[0086] In an exemplary embodiment of the present method, the particle is a solid particle selected from a pellet, a sphere, a granule and a biologic material, more in particular the solid particle is selected from a fertilizer, a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, more in particular selected from a fertilizer and a plant seed. The plant seed is preferably a seed of Spermatophyta, in particular at least one of Gym- nospermophyta, Pteridospermatophyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermophyta. The Gymnospermophyta is preferably selected from at least one of Cyadophyta, Ginkgophyta, Gnetophyta, Coniferophyta, and Cycadeoidophyta. The Pteridospermatophyta is preferably selected from at least one of Lyginopteridopsida, Medul- losopsida, Callistophytopsida, Peltaspermopsida, and Caytoniopsida. The Angiospermophyta is preferably selected from at least one of Monocotyledonae and Dicotyledonae. In particular the Angiospermophyta is selected from at least one of a cultivated crop plant and a flower plant.

[0087] In an exemplary embodiment of the present method of sealing cracks, voids or imperfections of a coating on a solid particle, the solid particle is selected from a fertilizer, a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, in particular selected from a fertilizer and a plant seed. The plant seed is preferably a seed of Spermatophyta, in particular at least one of Gymnospermophyta, Pteridospermatophyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermophyta. The Gymnospermophyta is preferably selected from at least one of Cyadophyta, Ginkgophyta, Gnetophyta, Coniferophyta, and Cycadeoidophyta. The Pteridospermatophyta is preferably selected from at least one of Lyginopteridopsida, Medullosopsida, Callistophytopsida, Peltaspermopsida, and Caytoniopsida. The Angiospermophyta is preferably selected from at least one of Monocotyledonae and Dicotyledonae. In particular the Angiospermophyta is selected from at least one of a cultivated crop plant and a flower plant.

[0088] In an exemplary embodiment of the present method of controlling a release rate of nutrients from a solid fertilizer, the controlling a release rate of nutrients from a solid fertilizer is prolonging nutrient diffusion from the solid fertilizer. In an exemplary embodiment of the present method, the release rate is controlled by the number of layers provided to the solid fertilizer. FIGURES

[0089] Figures la-lg show a schematic representations of particles comprising one or more layers of the bio-based coating of the present invention.

[0090] Figures 2a-2g show a schematic representations of one or more layers of the biobased coating of the present invention.

[0091] Figures 3a-3c show photographs of (non-)coated fertilizers.

[0092] Figures 4a-4b show photographs of (non-)coated urea.

[0093] Figure 5 shows a table with experimental results regarding swelling ratios related to type and number of bio-based coating layers.

[0094] Figures 6a-6d show photographs of coated fertilizers, coated with one first layer of the bio-based coating.

[0095] Figures 7a-7d show photographs of coated fertilizers, coated with two first layers of the bio-based coating.

[0096] Figures 8a-8d show photographs of coated fertilizers, coated with one first layer of the bio-based coating and a second layer of the bio-based coating.

[0097] Figures 9a-9d show test results of nitrogen release experiments in water under shear.

[0098] Figure lOa-lOb show test results of a dissolution experiment in water.

[0099] DETAILED DESCRIPTION OF FIGURES

[0100] In the figures:

[0101] 1 first layer, prime hydrophobic coating

[0102] 2 second layer, different from the first layer (1)

[0103] 3 particle, such as a mineral, a seed or a fertilizer.

[0104] 4 layer of anti-caking agent

[0105] Figure la shows a particle (3) comprising a bio-based coating comprising one first layer (1). The particle of the present invention comprises a bio-based coating, in particular for agricultural application, the bio-based coating comprising at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, comprising (la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and (lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1- 25 wt.%, and (1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer. The particle (3) is substantially encapsulated by the at least one first layer (1) of the bio-based coating, being a prime hydrophobic coating. The at least one first layer (1) is provided on the outer surface of the particle (3). In an exemplary embodiment the at least one first layer (1) of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

[0106] Figure lb shows a particle (3) comprising a bio-based coating comprising two first layers (1). In addition to one first layer (1), the particle (3) further comprises in addition a second layer, wherein the at least one second layer is provided on the outer surface of the at least one first layer (1), and wherein the second layer is a layer identical to the first layer (1) and provided on the first layer (1).

[0107] Figure 1c shows a particle (3) comprising a bio-based coating comprising one first layer and one second layer, different from the one first layer. In addition to one first layer (1), the particle (3) further comprises in addition a second layer, wherein the second layer is provided on the outer surface of the first layer (1), and wherein the second layer is a layer different from the first layer (1), and comprising a second biopolymer. In an exemplary embodiment the layer different from the at least one first layer (1) and comprising a second biopolymer, the second biopolymer is hydrophilic. In an exemplary embodiment the layer different from the at least one first layer (1) and comprising a second biopolymer is a water-su- perabsorbent layer with a high water-retention capacity, in particular wherein the water-su- perabsorbent layer has a swelling ratio of at least 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

[0108] Figure Id shows a particle (3) comprising a bio-based coating comprising two first layers (1) and one second layer (2), different from the first layer (1). In addition to one first layer (1), the particle (3) comprises two further layers provided on the outer surface of the first layer (1): one layer identical to the first layer (1) and provided on the first layer, and a layer different from the first layer (1): a second layer (2) comprising a second biopolymer.

[0109] Figure le shows a particle (3) comprising a bio-based coating comprising two first layers (1) and one layer of an anti-caking agent (4). In addition to one first layer (1), the particle (3) further comprises in addition a second layer, wherein the second layer is provided on the outer surface of the first layer (1), and wherein the second layer is a layer identical to the first layer (1) and provided on the first layer (1). Additionally, provided on the outer surface of the two first layers (1), the particle further comprises an additional layer of anti-caking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, wherein the additional layer of anti-caking agents provided on the outer surface of the outer layer.

[0110] Figure If shows a particle (3) comprising a bio-based coating comprising two first layers (1) and two second layers (2). In addition to one first layer (1), the particle (3) comprises three further layers provided on the outer surface of the first layer (1): one layer identical to the first layer (1) and provided on the first layer, and two layers different from the first layer (1), and comprising a second biopolymer.

[0111] Figure 1g shows a particle (3) comprising a bio-based coating comprising two first layers (1), one second layer (2) and one layer of anti-caking agent (4). In addition to one first layer (1), the particle (3) comprises two further layers provided on the outer surface of the at least one first layer (1): one layer identical to the at least one first layer (1) and provided on the at least one first layer, and a layer different from the at least one first layer (1), and comprising a second biopolymer. Additionally, provided on the outer surface of the layers, the particle further comprises an additional layer of anti-caking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, wherein the additional layer of anti-caking agent is provided on the outer surface of the outer layer.

[0112] Figure 2a shows a bio-based coating comprising one first layer (1). The bio-based coating of the present invention, in particular for agricultural application, comprises at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, comprising (la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and (lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, and (1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer. The at least one first layer (1) can be provided on the outer surface of a particle (3). In an exemplary embodiment the at least one first layer (1) of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

[0113] Figure 2b shows a bio-based coating comprising two first layers (1). In addition to one first layer (1), the bio-based coating further comprises in addition a second layer, wherein the at least one second layer is provided on the outer surface of the at least one first layer (1), and wherein the second layer is a layer identical to the first layer (1) and provided on the first layer (1).

[0114] Figure 2c shows a bio-based coating comprising one first layer and one second layer, different from the one first layer. In addition to one first layer (1), the bio-based coating further comprises in addition a second layer, wherein the second layer is provided on the outer surface of the first layer (1), and wherein the second layer is a layer different from the first layer (1), and comprising a second biopolymer. In an exemplary embodiment the layer different from the at least one first layer (1) and comprising a second biopolymer, the second biopolymer is hydrophilic. In an exemplary embodiment the layer different from the at least one first layer (1) and comprising a second biopolymer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

[0115] Figure 2d shows a bio-based coating comprising two first layers (1) and one second layer (2), different from the first layer (1). In addition to one first layer (1), the bio-based coating comprises two further layers provided on the outer surface of the first layer (1): one layer identical to the first layer (1) and provided on the first layer (1), and a layer different from the first layer (1): a second layer (2) comprising a second biopolymer.

[0116] Figure 2e shows a bio-based coating comprising two first layers (1) and one layer of anti-caking agent (4). In addition to one first layer (1), the bio-based coating further comprises in addition a second layer, wherein the second layer is provided on the outer surface of the first layer (1), and wherein the second layer is a layer identical to the first layer (1) and provided on the first layer (1). Additionally, provided on the outer surface of the two first layers (1), the bio-based coating further comprises an additional layer of anti-caking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, when provided on the outer surface of a particle, wherein the additional layer of anti-caking agent is provided on the outer surface of the outer layer.

[0117] Figure 2f shows a bio-based coating comprising two first layers (1) and two second layers (2). In addition to one first layer (1), the bio-based coating comprises three further layers provided on the outer surface of the at least one first layer (1): one layer identical to the at least one first layer (1) and provided on the first layer, and two layers different from the first layer (1), and comprising a second biopolymer.

[0118] Figure 2g shows a bio-based coating comprising two first layers (1), one second layer (2) and one layer of anti-caking agent (4). In addition to one first layer (1), the bio-based coating comprises two further layers provided on the outer surface of the at least one first layer (1): one layer identical to the at least one first layer (1) and provided on the at least one first layer, and a layer different from the at least one first layer (1), and comprising a second biopolymer. Additionally, provided on the outer surface of the layers, the bio-based coating further comprises an additional layer of anti-caking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, wherein the additional layer of anticaking agent is provided on the outer surface of the outer layer.

[0119] Figures 3a-3c show photographs of (non-)coated fertilizers. Figure 3a shows a number of fertilizer particles (NPK, 12:8: 16), spread over a surface. Figure 3b shows same fertilizer particle, but coated with one first layer (1) and one layer of anti-caking agent. Figure 3c(l-3) illustrates some individual particles during different states of the coating development.

[0120] Figures 4a-4b show photographs of (non-)coated urea. Figure 4a shows uncoated urea particles. Figure 4b illustrates how such urea particles look like when they comprise a bio-based coating comprising a layer comprising two first layers (1) and one layer of anticaking agent.

[0121] Figure 5 shows a table with experimental results regarding swelling ratios in grams per gram (g / g) related to type and number of bio-based coating layers. It is demonstrated that coating a fertilizer or a seed with one first layer (1) (prime coat) resulted in a swelling ratio of 15 g / g. Repeating the coating method, leading to a layer comprising two first layers (1), resulted in a bio-based coating with a swelling ratio of 29 g / g. Coating with a bio-based coating layer comprising a first and a second layer and wherein the second layer comprises a wastewater polymer (such as a glycoprotein), led to a bio-based coating with a swelling ratio of 24 g / g. As a prime coat a water-superabsorbent layer was applied.

[0122] Figures 6a-6d show photographs of coated fertilizers, coated with one first layer of the bio-based coating.

[0123] Figures 7a-7d show photographs of coated fertilizers, coated with two first layers of the bio-based coating.

[0124] Figures 8a-8d show photographs of coated fertilizers, coated with one first layer of the bio-based coating and a second layer of the bio-based coating.

[0125] Figures 9a-9d show test results of nitrogen release experiments in water performed under shear. Tests were performed with (un)coated fertilizer particles. Figure 9a shows the results of a raw uncoated fertilizer. Figure 9b shows the results of a raw fertilizer which was coated with a bio-based coating comprising one first layer (1). Figure 9c shows the results of a raw fertilizer which was coated with a bio-based coating comprising two first layers (1). Figure 9d shows the results of a raw fertilizer which was coated with a bio-based coating comprising one first layer (1) and one second layer (2), the one second layer (2) comprising a wastewater sludge glycoprotein polymer. The x-axis shows the time in minutes and the y- axis shows Mt / Moo, which demonstrates the fraction of fertilizer released at a particular time. Diffusion models were used for curve fitting, such as the Korrnsmeyer-Peppas model, n is a release exponent and predicts the release mechanism of a particle compound. K is the release rate constant. R2is the correlation value between raw and the fitted data. The high R2values (of above 0.9895) indicate a strong correlation between the data and the curve, confirming a good fit to the model. Figure 9a shows that after about 4000 minutes 100% of the fraction (Mt / M co=l) is released. After about 2000 minutes a Mt / Moo was measured of about 0.7. Figure 9b, wherein one first layer (1) of the bio-based coating of the invention was added, shows a delayed release wherein after about 2000 minutes a Mt / Mco was measured of about 0.6. Figure 9c, wherein two first layers (1) of the bio-based coating of the invention were added, shows a delayed release wherein after about 2000 minutes a Mt / Mco was measured of about 0.42. Figure 9d, wherein a first layer (1) and a second layer (2) comprising a wastewater sludge glycoprotein polymer, were added, shows a delayed release wherein after about 2000 minutes a Mt / Mco was measured of about 0.34. It can thus be concluded that nitrogen release of a fertilizer can be controlled by addition of the bio-based coating of the invention. Addition of a second first layer (1) demonstrated a surprising synergistic effect in terms of time needed to release nitrogen from the fertilizer through the layers of the biobased coating which was increased; leading to an improved controlled-release effect. When the second layer of the bio-based coating was -as demonstrated in Figure 9d- a second layer comprising a wastewater sludge glycoprotein polymer, the slower controlled-release effect was further increased. In other words, time needed to release nitrogen from the fertilizer through the layers of the bio-based coating was further increased, as the released fraction of fertilizer was further reduced. Figure 10a- 10b show test results of a dissolution experiments in water. Fertilizer particles were put in two flasks of water for two weeks in order to perform a coating dissolution test. The experiment is further explained in example 3.

[0126] EXAMPLES

[0127] Example 1

[0128] In order to test the protective properties of the bio-based coating, an experiment was carried out wherein seed particles (such as com kernel) were coated with one first layer of the bio-based coating as well as with one second layer comprising a wastewater sludge polymer. The term protective layer as used herein refers to a layer, which is protective in view of the coated material, thereby protecting the coated material from the outer environment. The coated seeds were put in water and it was found that after five hours as well as after 24 hours, the seeds were intact and covered by their swollen bio-based water-superabsorbent coating. Therewith, the protective value was clearly demonstrated.

[0129] Example 2

[0130] In a further experiment a coating dissolution test was performed. Fertilizer particles were put in two flasks, uncoated particles in one, and coated particles with a first water-superabsorbent layer and additionally with as second layer comprising a wastewater sludge polymer in another. Two Erlenmeyer flasks were used: raw fertilizer particles were added to flask 1. Raw particles coated with the two layers of the bio-based coating of the invention were added to flask 2. It was clearly demonstrated that after five hours the particles were fully disappeared in flask 1.

[0131] In flask 2 the fertilizer particles were still visible after five hours as well as after 7 days, and still coated and encapsulated by their swollen bio-based coating. This demonstrated that the bio-based coating keeps its integrity in water for a long period of time.

[0132] Example 3

[0133] In a further experiment fertilizer particles were put in two flasks of water for two weeks in order to perform another coating dissolution test. Two flasks were used: raw fertilizer particles were added to flask 1. Raw particles coated with one first water-superabsorbent layer of the bio-based coating of the invention were added to flask 2. After two weeks, it was observed that in flask 1 the fertilizer particles were disappeared. In flask 2 however, fertilizer particles were still visible, and still coated and encapsulated by their swollen biobased coating. Figure 10 visually illustrates the differences between the results in flask 1 (fig. 10a) compared to flask 2 (fig. 10b). This demonstrated that the bio-based coating keeps its integrity in water for a long period of time. In case of fertilizers this means that they are therefore able to release their nutrients slowly through their coating into the soil. This makes highly efficient use of nutrients possible. Additionally, this can be tailored dependent on the particular needs, such as by adding one or more layers of the bio-based coating of the invention to the fertilizer particles. Addition of layers will increase the diffusion time of nutrients and further improve the slower controlled-release properties.

[0134] Example 4

[0135] A fertilizer or seed particle respectively is covered or sealed by the biobased coating compositions (claim 1 : biopolymer, non-polar oil binder, plasticizer). It is found that this is not the case, or at least not to the same extent, for coatings comprising only partial components of claim 1, such as only the (bio)polymer or the non-polar oil binder. In addition, the present methods are preferred for simple fabrication of such coatings, for example, employing a rotary drum or pan coating apparatus.

[0136] Example 5

[0137] The coating as stand-alone or as fertilizer or seed coated product is high water swellable resulting in > 5g / g uptake, and preferably 15-35 g / g.

[0138] Example 6

[0139] The coating as stand-alone or on a fertilizer or seed particle is able to seal cracks upon contact with water due to the high water-swelling nature of coating compositions. This effect is not obtained in DI (thermoplastic coating), D3 (breaks down in water), or D5 (lignin and carnauba wax materials).

[0140] The present coating provides: A) a full particle coverage with; B) they may be designed to result in high water uptake (as is shown via a beaker test method or tea bag method); C) the water uptake and retention (swelling capacity) together also form basis of crack healing effect.

[0141] Comparison with prior art

[0142] Examples of WO 2020 / 096454 Al (DI), WO 2020 / 044189 Al (D3), and WO

[0143] 2024 / 003455 Al ((D5) were studied.

Claims

CLAIMS1. A particle (3), comprising a bio-based coating, in particular for agricultural application, in particular a water-soluble coating, the bio-based coating comprising at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, wherein the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer, in particular wherein the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, comprising(la) at least one first water-soluble biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, and(lb) at least one non-polar binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, wherein the non-polar binder is an oil-based binder, and(lc) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein all weight percentages are based on the total weight of the at least one first layer, wherein the particle is encapsulated by the bio-based coating, and wherein the at least one first layer is provided on the outer surface of the particle.

2. The particle according to claim 1, wherein the bio-based water based coating is bio-de- gradable.

3. The particle according to any of claims 1-2, wherein the bio-based water based coating comprises at least one browning reaction product, in particular at least one non-enzymatic browning reaction product, more in particular wherein the non-enzymatic browning reaction product is selected from a product of a chemical reaction between sugars and from a product of a chemical reaction between an amino acid and a sugar, more in particular at least one of a Maillard-reaction product and a caramelization-reaction product.

4. The particle according to any of claims 1-3, wherein the at least one first layer of the at least one layer is a hermetic layer, and / or wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g, and / or wherein the bio-based water based coating comprises 0-25 wt.% of a water-insoluble fibre, preferably 0-20 wt.%, more preferably 0-15 wt.%, most preferably 0-10 wt.%, in particular wherein the water-insoluble fibre is at least one of cellulose and a cellulose derivative.

5. The particle according to any of claims 1-4, wherein the non-polar binder is a non-impregnating oil-based binder, preferably a non-impregnating oil-based binder comprising at least one triglyceride, in particular a mixture of triglycerides, more preferably the non-impregnating oil-based binder is selected from at least one vegetable oil, and / orwherein the first biopolymer is selected from at least one of a polynucleotide, a polypeptide and a polysaccharide, preferably the at least one first biopolymer is selected from at least one of animal-based biopolymers, plant-based biopolymers, and microbial-based biopolymers, and / or wherein the at least one plasticizer is selected from at least one of di-alcohol, di-alkanol, poly-alcohol, poly-alkanol, carboxylic acid, carboxylic acid ester, amide, phosphate, and epoxide, in particular wherein the di-alcohol has a chain length of 2-24 carbon atoms, in particular 4- 18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the di-alkanol has a chain length of 2-24 carbon atoms, in particular 4- 18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the poly-alcohol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alkanol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alcohol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the poly-alkanol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the carboxylic acid has a chain length of 2-20 carbon atoms, in particular 4-16 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the carboxylic acid-ester has a chain length of 6-42 carbon atoms, in particular 8-38 carbon atoms, more in particular 10-34 carbon atoms, and / or wherein the bio-based coating further comprises at least one additive, in particular wherein the at least one additive is selected from at least one of a polyphenolic additive, and a crosslinker additive, in particular a cross-linker additive, more in particular a natural cross-linking compound.

6. The particle according to any of claims 1-5, wherein the bio-based water based coating further comprises at least one second layer (2), wherein the at least one second layer (2) is provided on the outer surface of the at least one first layer (1), wherein the at least one second layer is selected from at least one of a layer identical to the at least one first layer (1) and provided on the at least one first layer, and a layer different from the at least one first layer (1), and comprising a second biopolymer.

7. The particle according to claim 6, wherein the layer different from the at least one first layer (1) is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g.

8. The particle according to any of claims 1-7, further comprising an additional layer of anticaking agent, in particular an excess of a third biopolymer, for preventing coated particle aggregation, wherein the additional layer of anti-caking agent is provided on the outer surface of the outer layer, and / or wherein the at least one first layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm, and / or wherein the at least one first layer is a water-non-impregnating layer, and / or, wherein the at least one second layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm, and / or wherein the at least one second layer is hydrophilic, and / or wherein at least one layer selected from the at least one first layer and the at least one second layer is a gel-like layer, in particular a gel-like layer with a viscosity of > 1 Pa*s, in particular >10 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer, in particular a gel-like layer with a viscosity of < 200 Pa*s, in particular <150 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer, and / or wherein at least one layer selected from the at least one first layer and the at least one second layer has a stiffness of Young’s modulus between 1 and 5 GPa, at a temperature of 20°C., and / or wherein the particle is a solid particle selected from a pellet, a sphere, a granule and a biologic material, more in particular the solid particle is selected from a fertilizer, a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, more in particular selected from a fertilizer and a plant seed, in particular the plant seed is selected from a seed of Spermatophyta, in particular at least one of Gymnospermophyta, Pteridospermato- phyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermophyta, in particular selected from at least one of a crop plant and a flower plant, and / or wherein the particle has a cross-sectional size of 0.1-10 mm (sieve method), and / or wherein the particle is a controlled release particle, in particular a controlled release fertilizer, and / or wherein the bio-based water based coating further comprises at least one component selected from nutrients, pesticides, microbes, and colorants.

9. The particle according to any of claims 1-8, wherein at least one polymer selected from the first biopolymer and the second biopolymer is obtained from at least one of wastewater sludge and a wastewater treatment plant, and / or wherein the at least one second biopolymer is at least one anionic polymer, and / or wherein the bio-based water-soluble coating further comprises at least one cation, in particular at least one of ammonium, potassium, and sodium, and / or wherein the particle is a controlled release particle, in particular a controlled release fertilizer.

10. A bio-based water based coating comprising at least one layer, wherein at least one first layer (1) of the at least one layer is a protective layer, comprising(la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, wherein the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer, and(lb) at least one non-polar binder, wherein the non-polar binder is an oil-based binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular 1-25 wt.%, and(lc) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, wherein all weight percentages are based on the total weight of the at least one first layer.

11. The bio-based water based coating according to claim 10, wherein the bio-based water- soluble coating is bio-degradable, and / or wherein the bio-based water-soluble coating comprises at least one browning reaction product, in particular at least one non-enzymatic browning reaction product, more in particular wherein the non-enzymatic browning reaction product is selected from a product of a chemical reaction between sugars and from a product of a chemical reaction between an amino acid and a sugar, more in particular at least one of a Maillard-reaction product and a caramelization-reaction product, and / or wherein the bio-based water-soluble coating is water-swellable, and / or wherein the bio-based water-soluble coating comprises 0-25 wt.% of a water-insoluble fibre, preferably 0-20 wt.%, more preferably 0-15 wt.%, most preferably 0-10 wt.%, in particular wherein the water-insoluble fibre is at least one of cellulose and a cellulose derivative, and / or wherein the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer, and / or wherein the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14 g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g, and / or wherein the swelling ratio of the coating is at least 2 (vol. / vol.), in particular at least 5, more in particular 10-200, and / or wherein the non-polar binder is a non-impregnating oil-based binder, preferably a non-impregnating oil-based binder comprising at least one triglyceride, in particular a mixture of triglycerides, more preferably the non-impregnating oil-based binder is selected from at least one vegetable oil, and / orwherein the at least one first biopolymer is selected from at least one of a polynucleotide, a polypeptide and a polysaccharide, preferably the at least one first biopolymer is selected from at least one of animal-based polymers, plant-based biopolymers, and microbial-based biopolymers, and / or wherein the plasticizer is selected from at least one of di-alcohol, di-alkanol, poly-alcohol, poly-alkanol, carboxylic acid, carboxylic acid ester, amide, phosphate, and epoxide, in particular wherein the di-alcohol has a chain length of 2-24 carbon atoms, in particular 4- 18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the di-alkanol has a chain length of 2-24 carbon atoms, in particular 4- 18 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the poly-alcohol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alkanol has a chain length of 4-48 carbon atoms, in particular 6-40 carbon atoms, more in particular 8-36 carbon atoms, in particular wherein the poly-alcohol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the poly-alkanol comprises 4-100 hydroxyl groups, in particular 6-80 hydroxyl groups, more in particular 8-60 hydroxyl groups, in particular wherein the carboxylic acid has a chain length of 2-20 carbon atoms, in particular 4-16 carbon atoms, more in particular 4-12 carbon atoms, in particular wherein the carboxylic acid-ester has a chain length of 6-42 carbon atoms, in particular 8-38 carbon atoms, more in particular 10-34 carbon atoms, and / or wherein the bio-based water-soluble coating further comprises at least one additive, in particular wherein the at least one additive is selected from at least one of a polyphenolic additive and a cross-linker additive, in particular a cross-linker additive, more in particular a natural cross-linking compound.

12. The bio-based water-soluble coating according to claim 10 or 11, wherein the bio-based water-soluble coating further comprises an at least one second layer (2), wherein the at least one second layer (2) is provided on the outer surface of the at least one first layer (1), wherein the at least one second layer is selected from at least one of- a layer identical to the at least one first layer (1) according to claims 10 or 11, and- a layer different from the at least one first layer (1), and comprising a second biopolymer, and wherein, if the at least one second layer comprises both the layer identical to the at least one first layer as well as the layer different from the at least one first layer, the layer identical to the at least one first layer is in between the at least one first layer and the layer different from the at least one first layer.

13. The bio-based water-soluble coating according to claim 12, wherein the layer different from the at least one first layer (1) is a water-superabsorbent layer with a high water-retention capacity, in particular wherein the water-superabsorbent layer has a swelling ratio of at least 1.5 g / g, in particular 5 g / g, in particular at least 10 g / g, more in particular at least 14g / g, preferably between 10 and 60 g / g, more preferably between 14 and 55 g / g, most preferably between 20 and 50 g / g, and / or wherein the at least one first layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm, and / or wherein the at least one first layer is a water-non-impregnating layer, and / or, wherein the at least one second layer has a thickness of 50-5000 pm, in particular of 60-2500 pm, in particular of 70-1000 pm, more in particular of 80-500 pm, and / or wherein the at least one second layer is hydrophilic, and / or wherein at least one layer selected from the at least one first layer and the at least one second layer is a gel-like layer, in particular a gel-like layer with a viscosity of > 1 Pa*s, in particular >10 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer, in particular a gel-like layer with a viscosity of < 200 Pa*s, in particular <150 Pa*s at a temperature of 20°C, measured by a rheometer, such as a cone and plate rheometer, and / or wherein at least one layer selected from the at least one first layer and the at least one second layer has a stiffness of Young’s modulus between 1 and 5 GPa, at a temperature of 20°C.

14. The bio-based water-soluble coating according to any of claims 10-13, further comprising an additional layer of anti-caking agent, in particular an excess of a third biopolymer, wherein the additional layer of anti -caking agent is provided on the outer surface of the outer layer, and / or wherein at least one polymer selected from the first biopolymer and the second biopolymer is obtained from at least one of wastewater sludge and a wastewater treatment plant, and / or wherein the at least one second biopolymer is at least one anionic polymer, and / or wherein the bio-based water-soluble coating further comprises at least one cation, in particular at least one of ammonium, potassium, and sodium.

15. A method for manufacturing a coated particle comprising a bio-based water-soluble coating, in particular for agricultural application, the method comprising- providing a particle in a container, and in the container exposing the particle to (lb) at least one non-polar binder and optionally to (1c) at least one plasticizer,- adding to the container a powder comprising (la) at least one first biopolymer, thereby obtaining the coated particle, the coated particle comprising a particle encapsulated by a bio-based water-soluble coating, wherein the bio-based water-soluble coating comprises at least one first layer (1), the at least one first layer (1) comprising(la) at least one first biopolymer, in particular 50-98 wt.% of the at least one first biopolymer, in particular 55-95 wt.%, more in particular 60-90 wt.%, wherein the at least one first biopolymer of the at least one first layer of the at least one layer is a crosslinked polymer, and(lb) at least one non-polar binder, wherein the non-polar binder is an oil-based binder, in particular 0.1-35 wt.% of the non-polar binder, in particular 0.5-30 wt.%, more in particular1-25 wt.%, and(1c) optionally at least one plasticizer, in particular 0-49.9 wt.% of the at least one plasticizer, in particular 0-45 wt.%, more in particular 0.4-40, more in particular 0.8-35 wt.%, wherein the at least one first layer of the at least one layer is a water-superabsorbent layer with a high water-retention capacity, wherein all weight percentages are based on the total weight of the at least one first layer.

16. The method according to claim 15, wherein the method is repeated at least one time, thereby providing an at least one second layer on the outer surface of the at least one first layer, thereby obtaining a particle encapsulated by a bio-based water-soluble coating comprising at least two layers, wherein both at least two layers comprise at least one non-polar binder, at least one first biopolymer, and optionally at least one plasticizer.

17. The method according to claim 15 or 16, wherein an at least one further layer comprising a second biopolymer is provided on the outer surface of the coated particle, in particular by applying at least one of suspended biopolymers and aqueous-soluble biopolymers, in particular wherein the at least one further layer is a water-superabsorbent layer with a high waterretention capacity, and / or wherein a further layer of anti-caking agent is added, in particular an excess of a third biopolymer, wherein the additional layer of anti-caking agent is provided on the outer surface of the coated particle, for preventing coated particle aggregation, and / or wherein the powder comprising at least one first biopolymer has a particle size distribution of 150 pm with a standard deviation of 50 pm, and / or wherein the coated particle is subjected to a browning reaction, in particular a non-enzymatic browning reaction, in particular a chemical reaction selected from a chemical reaction between sugars and a chemical reaction between an amino acid, and a sugar, and / or wherein the particle is a solid particle selected from a pellet, a sphere, a granule, and a biologic material, more in particular the solid particle is selected from a fertilizer, a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, more in particular selected from a fertilizer, and a plant seed, in particular the plant seed is selected from a seed of Spermatophyta, in particular at least one of Gymnospermophyta, Pteridospermato- phyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermophyta, in particular selected from at least one of a crop plant and a flower plant.

18. A coated particle obtained by the method according to any of claims 15-17, in particular wherein the coated particle is a controlled-release particle, more in particular a controlled- release fertilizer.

19. A method of sealing cracks, voids or imperfections of a coating on a solid particle, comprising applying the method according to any of claims 15-17 to the particle, thereby providing the bio-based water-soluble coating to the outer surface of the solid particle, and providing water thereby swelling the coating and sealing the cracks, voids or imperfections of the coating on the solid particle.

20. The method according to claim 19, wherein the solid particle is selected from a fertilizer,a probiotic, a prebiotic, a plant seed, a food composition, and an animal feed composition, in particular selected from a fertilizer, and a plant seed, in particular the plant seed is selected from a seed of Spermatophyta, in particular at least one of Gymnospermophyta, Pteridosper- matophyta and Angiospermophyta, in particular the plant seed is a seed of Angiospermo- phyta, in particular selected from at least one of a crop plant and a flower plant.

21. A method of controlling a release rate of nutrients from a solid fertilizer, comprising applying the method according to any of claims 15-17 to the solid fertilizer, thereby providing the bio-based water-soluble coating to the outer surface of the solid fertilizer.

22. The method according to claim 21, wherein the controlling a release rate of nutrients from a solid fertilizer is prolonging nutrient diffusion from the solid fertilizer.

23. The method according to any of claims 21 or 22, wherein the release rate is controlled by the number of layers provided to the solid fertilizer.

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