Use of a keratin hydrolysate with high levels of free amino acids to stimulate emergence and early plant growth

Abstract

Use of a keratin hydrolysate comprising at least 88% by weight of free amino acids relative to the total weight of amino acids in the hydrolysate, the remaining amino acids in the hydrolysate being in the form of peptides having a molecular mass less than or equal to 800 Daltons, said hydrolysate comprising glutamic acid at a level of 8 to 13% by weight relative to the total weight of the hydrolysate and glycine at a level of 6 to 9% by weight relative to the total weight of the hydrolysate, for application to a seed to stimulate the development of the plant from which it originated at an early stage of growth and in particular to improve leaf development, to enhance root biomass, and to accelerate seedling emergence and establishment. Figure to be published with the abstract: none

Description

Title of the invention: Use of a keratin hydrolyzate with a high content of free amino acids to stimulate the emergence and early growth of plants

[0001] The invention relates to the field of agriculture and more particularly to the use of a keratin hydrolysate with high free amino acid contents applied to seeds to stimulate the development of the plants from which they originate at the early stage of their growth, and to increase their performance.

[0002] Various parameters can lead to delaying sowing, i.e. planting or starting crops after sowing. These parameters can be external to the seed, such as the availability of soil nutrients, the outside temperature and in particular the soil temperature; they can also be parameters specific to the seed, leading to an effect on its quality.

[0003] However, the early stage is a crucial stage of growth. In fact, sowing is generally carried out at the most favorable time of year, for example before summer so that the crops can take full advantage of the sunny months. Consequently, a delay in development at the early stage risks leading to slower plant development and therefore lower yields.

[0004] Various fertilizer compositions, called "starters", have been developed to increase the growth and yield of plants by stimulating the development of the root system of young plants.

[0005] These compositions are conventionally based on ammonium phosphate, however this type of composition has the disadvantage of being aggressive towards the seedling.

[0006] There are also "starter" formulations based on inoculums of microorganisms based on bacteria and / or mycorrhizal fungi, which aim to solubilize phosphorus and / or facilitate the plant's access to phosphorus. These formulations thus make it possible to practice agriculture that is more economical in mineral fertilizers with a "starter" effect and induced nutritional effects.

[0007] There is still a need for new products to improve early plant growth, particularly products that do not lead to imbalances and that are environmentally friendly and come from the circular economy.

[0008] Patent application WO2019 / 043128 A1 describes a keratin hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolyzate, the remainder of the amino acids in the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton, said hydrolyzate comprises L-cystine in a content ranging from 4 to 6% by weight, cysteine ​​in a content less than or equal to 0.1% by weight and tyrosine in a content less than or equal to 0.6% as well as a process for preparing this hydrolyzate.

[0009] The present invention aims to provide products intended to be applied in contact with plant seeds, to improve the early stage of development of the plant, that is to say to provide products having a “starter” effect.

[0010] The invention thus relates to the use of a keratin hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids of the hydrolyzate, the remainder of the amino acids of the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton, said hydrolyzate comprising glutamic acid in a content ranging from 8 to 13% by weight relative to the total weight of the hydrolyzate and glycine in a content ranging from 6 to 9% by weight relative to the total weight of the hydrolyzate, in application to a seed to stimulate the development of the plant derived from said seed at the early stage of its growth.

[0011] More particularly, the invention relates to the use of said keratin hydrolyzate for increasing root biomass, for improving plant emergence, crop establishment, growth and leaf precocity and for accelerating plant emergence and in particular for accelerating the growth rate up to the 6 to 8 leaf stage.

[0012] The hydrolyzate according to the present invention, rich in free amino acids, used in application in contact with seeds makes it possible to stimulate the development of seeds at the early stage of their growth, that is to say to present a "starter" effect. This use thus makes it possible to increase the performance at the early stage of seed growth and in particular to increase the root biomass. Consequently, it makes it possible to improve the rooting and therefore the establishment of the plant, to increase the speed of emergence of the plant, in particular the speed of growth up to the 6 to 8 leaf stage, which also allows an earlier appearance of flowers (flower buds).

[0013] Improving root development during the first few days after planting the seed allows seedlings to absorb water and nutrients more efficiently so the plant can grow and produce more quickly, while reducing the risk of early stress.

[0014] Roots are important for acquiring water and nutrients, as well as for anchoring the plant in the growing medium. Roots are also the part of the plant where interaction with soil microorganisms takes place and they constitute an important nutrient storage reserve.

[0015] Rooting development corresponds to an increase in root growth in length, and / or in degree of branching, and / or an increase in rooting depth, and / or an increase in cumulative root length.

[0016] Increasing early emergence, particularly the early appearance of the first leaves, is a condition for good subsequent plant development and better production.

[0017] The use of the hydrolyzate according to the present invention is part of the search for more sustainable and resilient agriculture: it can be used in quantities much lower than the quantities used for fertilizers. Indeed, without wishing to be bound by any theory, the hydrolyzate according to the invention is not intended to provide nutrients such as carbon, nitrogen, phosphorus, for plants but rather to allow the young plant to increase its capacity to assimilate nutrients from the soil, in particular its capacity to root and develop its root biomass (quantity), to allow it to accelerate its leaf development and to emerge more quickly, in order to have a lasting effect on its growth.

[0018] The use of the hydrolyzate according to the present invention therefore makes it possible to reduce soil fertilization. The use according to the invention therefore indirectly produces effects on the soil since it allows a reduction in conventional chemical inputs and fertilizers.

[0019] Other aspects, advantages, properties of the invention will emerge clearly from the description, in particular from the examples which follow, for information purposes only and in no way limiting. Detailed description

[0020] Definitions

[0021] By “seed” is meant any reproductive organ, in particular any dormant organ and particularly seeds, tubers, bulbs.

[0022] By "sowing" we mean the placing of the seed on the growing medium where the seeds are planted and, by extension, we mean the young plants grown from the seeds.

[0023] By "early stage of growth", as used herein, is generally meant the period between planting the seed and the 6 to 8 leaf stage. Generally this early stage corresponds to a period of up to 2 to 8 weeks from the seed being planted. Of course this period depends on the plant species in question.

[0024] The expressions “plant a seed” or “cultivate a seed” are used interchangeably.

[0025] Preferably the seeds used according to the invention are chosen from the seeds of cereal plants such as wheat, corn, barley; seeds of field crops such as potatoes, beets; and vegetable seeds such as lettuce and tomatoes.

[0026] Hydrolyzate

[0027] The hydrolyzate used according to the present invention is distinguished by its high level of amino acids in free form: at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolyzate, the remainder also being in highly hydrolyzed form since the remainder of the amino acids in the hydrolyzate is in the form of small peptides having a molecular mass less than or equal to 800 Dalton. This is established by means of an HPLC analysis method on a gel permeation chromatographic column which makes it possible to determine the distribution of molecular weights of products containing proteins and / or peptides and / or free amino acids. The sample is dissolved: the distribution of molecular weights is made on the soluble part of the products to be analyzed. Then the sample is injected into HPLC, followed by UV detection. The separation of the different compounds is done according to their molecular size.

[0028] Advantageously, the hydrolyzate used according to the present invention is obtained from natural animal keratin materials, in particular poultry, advantageously from poultry feathers. As poultry, mention may be made of hens, in particular laying hens, chickens, turkeys, ducks, geese, etc. The natural keratin materials may also be chosen from animal hair, in particular pig bristles, animal hooves, animal nails.

[0029] In particular, advantageously the hydrolyzate according to the present invention is not obtained from human keratin such as hair.

[0030] According to a first preferred variant of the invention, the hydrolyzate has the following composition in total amino acids: an aspartic acid content ranging from 5 to 8% by weight, preferably ranging from 6 to 7% by weight; a threonine content ranging from 3 to 6% by weight, preferably from 4 to 5% by weight; a serine content ranging from 9 to 14% by weight, preferably ranging from 10 to 12% by weight; a glutamic acid content ranging from 9 to 11% by weight; a glycine content ranging from 6.5 to 8% by weight; an alanine content ranging from 4 to 6% by weight, preferably from 4 to 5% by weight; a valine content ranging from 6 to 10% by weight, preferably ranging from 6.5 to 8% by weight; a methionine content ranging from 0.1 to 0.6% by weight; an isoleucine content ranging from 4 to 6% by weight, preferably ranging from 4 to 5% by weight; a leucine content ranging from 6 to 9% by weight, preferably ranging from 7 to 8% by weight;a phenylalanine content ranging from 2 to 5% by weight; a lysine content ranging from 1 to 3% by weight, a histidine content ranging from 0.4 to 1% by weight; an arginine content ranging from 5.5 to 6.5% by weight; a proline content ranging from 8.5 to; 11% by weight, a tryptophan content of less than 0.1%, preferably 0% by weight relative to the total weight of the hydrolyzate.

[0031] According to a second preferred variant of the invention, the hydrolyzate has a cystine content ranging from 1 to 2.5% by weight, preferably ranging from 1 to 2% by weight and a tyrosine content ranging from 0.1 to 1% by weight relative to the total weight of the hydrolyzate.

[0032] The amino acids are measured according to a method adapted from EC Regulation 152 / 2009.

[0033] According to this method, for the determination of the quantities of total amino acids, hydrolysis using an acid is first carried out.

[0034] For the determination of the quantities of free and total amino acids, the amino acids are separated by chromatography ("HPLC" or "CLHP" in English) preferably with an ion exchange column and assayed by reaction with ninhydrin and photometric detection generally at 570 nm.

[0035] According to a third preferred variant, the hydrolyzate comprises the following free amino acids: at least 95% of aspartic acid in free form by weight relative to the total weight of aspartic acid in the hydrolyzate; at least 95% of threonine in free form by weight relative to the total weight of threonine in the hydrolyzate; at least 95% of serine in free form by weight relative to the total weight of serine in the hydrolyzate; at least 93% of glutamic acid in free form by weight relative to the total weight of glutamic acid in the hydrolyzate; at least 93% of glycine in free form by weight relative to the total weight of glycine in the hydrolyzate; at least 93% of alanine in free form by weight relative to the total weight of alanine in the hydrolyzate; at least 95% of methionine in free form by weight relative to the total weight of methionine in the hydrolyzate;at least 93% of phenylalanine in free form by weight relative to the total weight of phenylalanine in the hydrolyzate; at least 95% of proline in free form by weight relative to the total weight of proline in the hydrolyzate. ;

[0036] As shown in Table 2, the majority of amino acids are at least 95% in free form relative to the total weight of said amino acid in the hydrolyzate.

[0037] The free amino acids are in their natural, undenatured L (Levorotatory) configuration, thus rapidly available to soil microorganisms. In addition, the hydrolyzate used according to the invention has high levels of free branched amino acids: valine, leucine and isoleucine. However, these branched amino acids are known to be more difficult to release under identical processing conditions.

[0038] Advantageously, the total amino acid content (free and bound) of the hydrolyzate used according to the invention, i.e. the active material of the hydrolyzate, ranges from 40% to 95%, preferably 45% to 94% by weight relative to the total weight of the hydrolyzate, the hydrolyzate further comprising mineral matter and water. As already mentioned the amino acids of the hydrolyzate according to the invention are essentially free amino acids.

[0039] Preferably, the mineral matter content of said hydrolyzate, preferably sodium or potassium chloride, phosphate or sulfate, is less than or equal to 9% by weight, preferably less than 8% by weight relative to the total weight of the hydrolyzate. This mineral matter content is determined after calcination of the hydrolyzate at 550°C for 4 hours.

[0040] The hydrolyzate used according to the invention is also soluble in water, in fact 1 g of hydrolyzate is soluble in 5 ml of water. In fact, the hydrolyzate contains a very large majority of water-soluble amino acids in number and in weight. In addition, the low level of cystine and tyrosine in the hydrolyzate used in a preferred manner also contributes to making it very water-soluble. This instant solubility is an advantage for the farmer using the hydrolyzate in liquid form, because it makes it possible to avoid all the practical problems encountered during spraying, in particular the clogging of the sprayer nozzles... This advantage has been observed in particular when the hydrolyzate is used at doses of 0.1 to 5 kg per hectare of planted area. Furthermore, this also gives it very high hygroscopicity, a very interesting property for the application of the final product to seeds.

[0041] The amino acids in the hydrolyzate can be mixed with other phytopharmaceutical and / or fertilizer products applied in solution to the soil and plants; in fact, they allow the end user to avoid adding additional passes of agricultural machinery over the fields.

[0042] Process for preparing the hydrolyzate

[0043] The hydrolyzate used according to the invention is a chemical hydrolyzate, in fact it is obtained by implementing at least one step of chemical, acid hydrolysis. Thus the keratin hydrolyzate used according to the invention is prepared from an animal keratin material, preferably from poultry, according to a preparation process comprising at least one step of acid hydrolysis using a strong acid chosen from hydrochloric, phosphoric and sulfuric acids, preferably hydrochloric acid.

[0044] Advantageously, the hydrolyzate used according to the invention is obtained by a preparation process in which the keratin material is a keratin material, preferably from poultry, comprising at least the following steps, in this order: - subjecting the keratin material to at least one acid hydrolysis under conditions capable of obtaining a hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolyzate, the remainder of the amino acids in the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton, - possibly dry it.

[0045] Preferably, tyrosine and cystine are extracted from said hydrolyzate before possible drying, preferably this extraction is carried out using a mineral base.

[0046] The hydrolyzate according to the invention is obtained from natural keratin materials, advantageously from poultry feathers. Examples of poultry include hens, chickens, turkeys, ducks, geese, etc.

[0047] In particular, the hydrolyzate according to the present invention is not obtained from human keratin such as hair.

[0048] The process for preparing the keratin hydrolyzate according to the invention implements at least one hydrolysis by means of an acid under conditions capable of obtaining a hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids of the hydrolyzate, the remainder of the amino acids of the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton.

[0049] The percentage of small peptides - having a molecular mass less than or equal to 800 Dalton - in the hydrolyzate generally ranges from 5 to 12% by weight relative to the total weight of the hydrolyzate.

[0050] The hydrolysis of keratin is carried out by means of an acid, preferably a strong acid chosen from hydrochloric, phosphoric and sulfuric acids, preferably hydrochloric acid. Preferably the strong acid is used in a concentration ranging from 10 to 30%, preferably from 15 to 25%.

[0051] The hydrolysis is generally carried out for a period ranging from 1 hour to 8 hours, preferably from 6 to 7 hours at a temperature ranging from 100 to 115°C, preferably from 110 to 115°C. The hydrolysis can be carried out in several stages, for example 2, 3 or 4 stages.

[0052] According to a particular variant, the hydrolysis is carried out in two stages: - a first hydrolysis carried out at a temperature ranging from 60 to 80°C for a period ranging from 4 to 5 hours then - a second hydrolysis carried out at a temperature ranging from 100 to 115°C for a period ranging from 5 to 7 hours, both hydrolyses can be carried out without an intermediate pause step or by carrying out an intermediate pause step of between 1 hour and 7 days.

[0053] More precisely, the first hydrolysis is carried out at 72°C for 4.5 hours and the second hydrolysis is carried out at 107°C for 6 hours, with an intermediate break of 24 to 80 hours being carried out between the two hydrolyses.

[0054] The hydrolysis, carried out in one or more stages, is advantageously followed by at least one stage of extraction of cystine and tyrosine.

[0055] The step of extracting cystine and tyrosine is carried out using a base, preferably chosen from sodium hydroxide, potassium hydroxide, preferably sodium hydroxide. The addition of a base to the hydrolyzate makes it possible to precipitate the less soluble amino acids (mainly cystine, tyrosine), thus making them separable from the liquid phase by suitable techniques, such as filtration or spinning.

[0056] The steps of hydrolysis and extraction of cystine and tyrosine can be followed by optional steps of purification of the hydrolyzate obtained.

[0057] The invention also relates to a process for preparing the hydrolyzate in which the tyrosine and cystine are extracted from said hydrolyzate and the liquid phase obtained after the extraction of the cystine and tyrosine is desalted.

[0058] In particular, the liquid phase obtained after the extraction of cystine and tyrosine can be desalted to extract the salts formed by the action of the base on the acid, and thus obtain a desalted liquid phase.

[0059] The steps of hydrolysis, extraction of cystine and tyrosine, and desalination, can be followed by optional steps of concentration and drying, for example by atomization.

[0060] The desalination, concentration and drying steps are conventional steps whose implementation falls within the skills of those skilled in the art.

[0061] The step of extracting cystine and tyrosine can be followed by an optional step of recovering certain amino acids from the precipitate by re-dissolving it in acid, then re-precipitating it with a base, the amino acids to be recovered then being in the liquid phase, which can be added to the liquid phase resulting from the first spinning.

[0062] Preferably, the hydrolyzate used according to the present invention comprises less than 1% by weight of tyrosine relative to the total weight of the hydrolyzate, preferably less than 0.5%, more preferably, the hydrolyzate does not contain tyrosine, the only traces of tyrosine being due to the limits of the operating conditions and the equipment used during the extraction step.

[0063] Preferably, the hydrolyzate according to the present invention comprises less than 2.5%, preferably less than 1.5% and more preferably less than 1% by weight of cystine relative to the total weight of the hydrolyzate, more preferably, the hydrolyzate does not contain cystine.

[0064] Furthermore, since the hydrolyzate according to the invention is not obtained under reducing conditions, it does not comprise cysteine.

[0065] Uses

[0066] According to the present invention, the hydrolyzate is advantageously used either as a mixture with the seeds or as an application to the seeds placed in sowing rows. In particular, the hydrolyzate is applied in a mixture with the seeds by coating, dusting, spraying, watering the seeds or by application on the seeds placed in sowing rows.

[0067] The mixing of the hydrolyzate with the seeds is carried out before planting the seeds, by coating, dusting, spraying or watering depending on the form of the hydrolyzate. More particularly, the coating can be carried out by sprinkling the seed on a conveyor belt or by mixing the seeds in the presence of the solution in a rotating drum.

[0068] According to a first variant, the hydrolyzate is used in a mixture with the seeds in an amount ranging from 500 g to 5000 g, preferably from 1000 g to 2000 g of active hydrolyzate material per 1000 kg (1 tonne) of seeds.

[0069] Generally, the mixture is carried out within 24 hours before planting, preferably just before planting.

[0070] According to a second variant, the hydrolyzate is used in application to the seeds placed in sowing rows in an amount ranging from 500 g to 5000 g, preferably 1500 g of active hydrolyzate material per 10000 m2 of planted surface, more particularly per 10000 m2 of sowing rows.

[0071] Generally, the treatment, that is to say the use of the hydrolysate, is carried out on the seeds placed in sowing rows before being buried.

[0072] The hydrolyzate may also be used in liquid form in the form of an aqueous composition comprising from 45 to 55% and preferably 53% by weight of keratin hydrolyzate in solid form relative to the total weight of said composition. The aqueous composition may be the carrier of other active ingredients and be diluted accordingly.

[0073] According to the present invention, the hydrolyzate can be used with at least one agent chosen from trace elements, minerals, lignin and its derivatives, humic acid, fulvic acid, algae extracts, vinasse, molasses and organic materials such as manure, co-products of animal origin.

[0074] According to the present invention, the keratin hydrolyzate can also be used with at least one agent chosen from phytopharmaceutical products, biocontrol agents, plant biostimulants, products based on microorganisms, in particular as a coating.

[0075] In particular, the hydrolyzate can be used with at least one microorganism chosen from fungi and bacteria. The fungi are preferably chosen from endomycorrhizal fungi; Trichoderma spp and in particular Trichoderma harzianum, Trichoderma asperellum, Trichoderma atroviride; Coniothyrium minitans; Glomus mosseae and Glomus spp.; Sac-charomyces cerevisiae and the bacteria are preferably chosen from Brady-rhizobium japonicum, Bacillus spp in particular Bacillus amyloliquefaciens and Bacillus mucilaginosus; Pseudomonas spp in particular Pseudomonas fulva, Pseudomonas fluorescens and Pseudomonas putida.

[0076] As examples, the products presented in the following table 1 can be cited.

[0077] [Tables 1] Supplier Product Mushrooms Bacteria Actura® Resid MG® Endomycorrhizal fungi Agrifutur® Nitrogen® Bradyrhizobium japonicum Agrostar® Baci Start M4® Bacillus amyloli-quefaciens BASF® Rhizoflo soja® Bradyrhizobium japonicum Biovitis® Cérès Carpoes Heles® Trichoderma harzianum Pseudomonas fluorescens Bacillus methylo-trophicus Cybele Agro Care® Bacteriolis Rhizo-bacteriolis® Pseudomonas fulva + Pseudomonas fluorescens Compo expert® Agrosil turf Argin® Bacillus amyloli-quefaciens De Sangosse® Rizoliq Top® Bradyrhizobium japonicum FCA® Myco'sol C® Coniothyrium minitans Trichoderma as-perellum Pseudomonas fluorescens Pseudomonas putida Fertemis® Fertevie Rhiz® Bacillus amyloli-quefaciens Eléphant vert® Ovalis rhizofertil® Pseudomonas putida Gaiago SAS® Free PK® Bacillus muci-laginosus If Tech® Mycor® Endomycorrhizal fungus Inoculum Plus® Symbivit® Endomycorrhizal Fungi Hello Nature® CONDOR® Endomycorrhizal Fungi Trichoderma atroviride Rhizosphere Bacterium Hello Nature® TEAM Horto® Endomycorrhizal Fungi Trichoderma atroviride Glomus mosseae Rhizosphere Bacterium Hello Nature® TEAM Encoping® Endomycorrhizal Fungi Trichoderma atroviride Glomus mosseae Rhizosphere Bacterium Hello Nature® TIFI® Trichoderma atroviride Glomus spp. Rhizosphere bacteria Lallemant Plant Care® Rhizocell® Bacillus amyloliquefaciens sp Plantworks® Root grow® Endomycorrhizal fungi Premier Tech GHA® Myke Pro® Endomycorrhizal fungi Koppert® Trianum-P® Trichoderma harzianum Agrauxine® Tri-Soil® trichoderma atroviride Agrauxine® Moka® Saccharomyces ce-revisiae

[0078] The following examples are intended to illustrate the invention without limiting its scope. Examples

[0079] Example 1- Hydrolyzate

[0080] Preparation of the hydrolyzate

[0081] Hydrolysis

[0082] In a 55,000 liter reactor / hydrolyzer, 9000 kg of poultry feathers containing 50% dry matter are introduced. Chemical hydrolysis is carried out by adding 18,000 liters of hydrochloric acid (23%), the hydrolysis is carried out at 72°C for 4.5 hours.

[0083] The product obtained is stored for 48 hours, allowing its temperature to naturally rise to room temperature. Then, a second chemical hydrolysis is carried out by heating to 107°C for 6 hours without adding acid.

[0084] The hydrolyzate obtained comprises 88% by weight of free amino acids, the remainder of the amino acids in the hydrolyzate being in the form of small peptides having a molecular mass less than or equal to 800 Dalton.

[0085] Purification

[0086] The hydrolysate is then decanted in order to remove the fat provided by the keratinous material which floats on the surface of the aqueous phase. The excess hydrochloric acid introduced during the hydrolysis stage is removed. 8000 kg of concentrate are recovered. Then 4500 kg of water are added to obtain 12500 kg of diluted concentrate.

[0087] pH adjustment

[0088] Sodium hydroxide at 30.5% is added to the hydrolysate to bring the pH to a value between 4 and 5. When the sodium hydroxide is added, the less soluble amino acids, notably cystine, tyrosine, leucine and isoleucine, precipitate at least partially. The other amino acids remain completely in solution in the liquid phase.

[0089] Spin

[0090] The suspension is then placed in a spin dryer, to separate the precipitate (2000 kg), and recover the liquid phase (17000 kg) in a tank.

[0091] Recovery of certain amino acids from the precipitate

[0092] The precipitate (2000 kg) is redissolved in approximately 4% hydrochloric acid (7000 kg), decolorized by passing through charcoal, then the solution is neutralized by adding 30% sodium hydroxide (1250 kg). A new precipitate forms, which is separated by spinning: 650 kg of precipitate and 8750 kg of liquid phase are obtained.

[0093] Meeting of liquid phases and desalination

[0094] The liquid phases from the first spinning (17000 kg) and the second spinning (8750 kg) are combined and desalinated jointly by electrodialysis to give approximately 17500 kg of desalinated liquid phase.

[0095] Concentration and / or drying

[0096] The liquid phase is concentrated by evaporation of water to reach 55% dry matter (hydrolyzate in liquid form), it can then be dried by atomization in order to obtain a hydrolyzate in powder form containing 98% dry matter.

[0097] Table 2 shows the contents and weight fractions of each of the amino acids in the hydrolyzate in powder form.

[0098] [Tables2] Content (% weight) in the composition Weight fraction Free AA / Total AA Aspartic Acid 6.44 98% Threonine 4.32 99% Serine 10.72 100% Glutamic Acid 9.78 95% Glycine 7.30 97% Alanine 4.38 97% Valine 7.30 70% Cystine 1.93 63% Methionine 0.48 100% Isoleucine 4.37 77% Leucine 7.23 92% Tyrosine 0.77 81% Phenylalanine 4.44 96% Lysine 1.71 91% Histidine 0.60 93% Arginine 5.84 92% Proline 9.89 99% Total 87.44%

[0099] The free amino acid content is 93.1% by weight relative to the weight of total amino acids (free and bound). In the following examples, when the hydrolyzate according to Example 1 is used in powder form, it corresponds to a dry matter content of 98.0% by weight and a nitrogen content of 12%; when the hydrolyzate according to Example 1 is used in liquid form, it corresponds to a dry matter content of 55% and a nitrogen content of 7.1%.

[0100] In the following examples, statistical differences between values ​​were determined by the ANOVA method.

[0101] Example 2 - Application to corn seeds

[0102] Device and protocol

[0103] KWS Armoris variety maize seeds were placed in seed rows using a seed drill - to ensure uniform sowing - at a density of 90,000 maize seeds per 10,000 m2, i.e. per hectare.

[0104] Then the hydrolyzate prepared in Example 1 was applied by spraying in the seed rows, directly onto the seedlings, in a quantity corresponding to 1.5 kg of hydrolyzate in powder form (in a slurry of 200 L of water) per 10,000 m2 of planted surface (seed rows).

[0105] The seeds were then buried, that is to say covered with earth.

[0106] As a control, untreated corn seeds of the same variety were planted at the same density of 90,000 corn seeds per 10,000 m2.

[0107] The growth stage of maize seeds was determined using the BBCH scale for cereals. According to this scale, codes 10 to 19 correspond to leaf development, in particular codes 17 and 18 correspond respectively to the presence of 7 unfolded leaves and 8 unfolded leaves.

[0108] Table 3 represents the average BBCH stage, reached after 6 weeks, of seeds treated with the hydrolysate vs. the untreated control.

[0109] [Tables3] Treatment Average BBCH stage, reached after 6 weeks BBCH Statistical test % increase compared to the control Untreated control 17 a - Treatment with the hydrolysate of example 1 18.3 b +7.6%

[0110] The use of the hydrolyzate according to the invention makes it possible to obtain plants having on average 1 leaf more than the control, i.e. 8 leaves vs. 7 leaves for the control. This result is statistically significant (p<0.05). [YES] Example 3- Application to wheat seeds

[0112] Triticum aestivum wheat seeds were coated with the hydrolysate prepared in Example 1. The planting density was 230 kg per 10000 m2.

[0113] The seeds were coated with the hydrolyzate in powder form prepared in Example 1 at a dose of 1 kg per 1000 kg (1 tonne) of seeds in a volume of 1.5 L of water or at a dose of 1.4 kg per 1000 kg (1 tonne) of seeds in a volume of 2 L of water, i.e. a first example (3.1) carried out according to a ratio of 100 g of hydrolyzate / 100 kg of seeds and a second example (3.2) carried out according to a ratio of 140 g of hydrolyzate / 100 kg of seeds.

[0114] Then the sowing was carried out as follows: the seeds were planted according to the following protocol: 230 kg of seeds per 10,000 m2.

[0115] As a comparative example, the same quantity of untreated seeds were planted according to the same protocol.

[0116] The quantity of root biomass was measured at the BBCH 12 stage, i.e. at the stage corresponding to the presence of 2 unfolded leaves. The measurements were carried out 2 months after sowing.

[0117] Root biomass was carried out on 20 plants. The root system is taken after cutting it at the collar, i.e. by taking only the underground part of the plant, i.e. by removing the aerial part.

[0118] Table 4 represents the weight of root biomass reached after 2 months of plants from seeds treated with hydrolysate vs. the control corresponding to plants from untreated seeds.

[0119] [T ables 4] Treatment Root biomass (in g) reached after 2 months Weight (in g) Statistical test % increase compared to the control Untreated control 2.65 b - Treatment 3.1 (100g of powdered hydrolysate per 100 kg of seeds) 2.96 a +11.7% Treatment 3.2 (140g of powdered hydrolysate per 100 kg of seeds) 2.99 a +12.8%

[0120] The use of the hydrolyzate according to the invention allowed a significant increase in root biomass at BBCH stage 12: example 3.1 led to obtaining a root biomass rate of +11.7% compared to the control and example 3.2 led to obtaining a root biomass rate of +12.8% compared to the control. The hydrolyzate according to the invention allows good rooting and therefore good implantation.

[0121] Example 4- Application to potato seeds

[0122] Voyager variety potato tubers were coated with the hydrolyzate prepared in Example 1.

[0123] The coating (example 4.1) was carried out by spraying 1000 kg of tubers with 1 kg of hydrolysate from example 1 dissolved in 1 L of water.

[0124] Then the sowing was carried out in the following manner: the coated tubers were planted according to a protocol respecting the density of 35,000 tubers per 10,000 m2.

[0125] As a control (comparative example 4.2), the same quantity of untreated tubers was planted according to the same protocol.

[0126] The amount of raised feet was measured after 39 days. The measurements were carried out on 20 blocks for each of the 2 examples 4.1 and 4.2 respectively. Each block is a 10 m length of mound with a width of 90 cm, in which the number of raised feet is counted.

[0127] Table 5 represents the number of feet raised per block (10 linear m) after 39 days

[0128] [Tables5] Treatment Results at D39 after sowing Number of feet raised / block Statistical test % increase compared to the control Untreated control 4.2 18.3 a - Treatment 4.1 with the hydrolyzate of example 1 25.9 b +41.5%

[0129] The use of the hydrolysate according to the invention allowed a very highly significant improvement in the vigour of the emergence after 39 days: example 4.1 according to the invention led to obtaining a number of raised feet 41.5% higher than that of the control group (comparative example 4.2). This result is very highly significant (THS, P<0.001).

[0130] Conclusions

[0131] Hydrolyzate 1, in accordance with the invention, whether in liquid or solid form, makes it possible to significantly improve the vigor and early growth of plants grown from treated seeds. The hydrolyzate according to the invention has a “starter” effect in the early stages of plant development: earlier development of the leaf and root systems, faster emergence of the plants and better establishment.

Claims

Claims

1. Use of a keratin hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolyzate, the remainder of the amino acids in the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton, said hydrolyzate comprising glutamic acid in a content ranging from 8 to 13% by weight relative to the total weight of the hydrolyzate and glycine in a content ranging from 6 to 9% by weight relative to the total weight of the hydrolyzate, in application to a seed to stimulate the development of the plant derived from said seed at the early stage of its growth,the hydrolyzate being used in a mixture with the seeds in an amount ranging from 500 g to 5000 g of active hydrolyzate material per 1000 kg of seeds or in application to the seeds placed in seed rows in an amount ranging from 500 g to 5000 g of active hydrolyzate material per 10000 m2 of planted surface, more particularly per 10000 m2 of seed rows, the hydrolyzate having the following composition in total amino acids: an aspartic acid content ranging from 5 to 8% by weight; a threonine content ranging from 3 to 6% by weight; a serine content ranging from 9 to 14% by weight; an alanine content ranging from 4 to 6% by weight; a valine content ranging from 6 to 10% by weight; a methionine content ranging from 0.1 to 0.6% by weight; an isoleucine content ranging from 4 to 6% by weight; a leucine content ranging from 6 to 9% by weight; a phenylalanine content ranging from 2 to 5% by weight; a lysine content ranging from 1 to 3% by weight,a histidine content ranging from 0.4 to 1% by weight; an arginine content ranging from 5.5 to 6.5% by weight; a proline content ranging from 8.5 to 11% by weight, a tryptophan content of less than 0.1% by weight relative to the total weight of the hydrolyzate.,

2. Use according to claim 1 wherein the hydrolyzate has the following composition in total amino acids: an aspartic acid content ranging from 6 to 7% by weight; a threonine content ranging from 4 to 5% by weight; a serine content ranging from 10 to 12% by weight; a glutamic acid content ranging from 9 to 11% by weight; a glycine content ranging from 6.5 to 8% by weight; an alanine content ranging from 4 to 5% by weight; a valine content ranging from 6.5 to 8% by weight; a isoleucine content ranging from 4 to 5% by weight; a leucine content ranging from 7 to 8% by weight; a tryptophan content of 0% by weight relative to the total weight of the hydrolyzate.

3. Use according to any one of the preceding claims in which the hydrolyzate has a cystine content ranging from 1 to 2.5% by weight, preferably ranging from 1 to 2% by weight and a tyrosine content ranging from 0.1 to 1% by weight relative to the total weight of the hydrolyzate.

4. Use according to any one of the preceding claims wherein the hydrolyzate comprises the following free amino acids: at least 95% of aspartic acid in free form by weight relative to the total weight of aspartic acid in the hydrolyzate; at least 95% of threonine in free form by weight relative to the total weight of threonine in the hydrolyzate; at least 95% of serine in free form by weight relative to the total weight of serine in the hydrolyzate; at least 93% of glutamic acid in free form by weight relative to the total weight of glutamic acid in the hydrolyzate; at least 93% of glycine in free form by weight relative to the total weight of glycine in the hydrolyzate; at least 93% of alanine in free form by weight relative to the total weight of alanine in the hydrolyzate; at least 95% of methionine in free form by weight relative to the total weight of methionine in the hydrolyzate;at least 93% of phenylalanine in free form by weight relative to the total weight of phenylalanine in the hydrolyzate; at least 95% of proline in free form by weight relative to the total weight of proline in the hydrolyzate.;

5. Use of a keratin hydrolyzate according to any one of the preceding claims in which the seed is chosen from cereal plant seeds such as wheat, corn, barley; field crop plant seeds such as potatoes, beets; and market garden seeds such as salads and tomatoes.

6. Use of a keratin hydrolyzate according to any one of the preceding claims wherein the hydrolyzate is applied in admixture with the seeds by coating, dusting, spraying, watering the seeds or by application to the seeds placed in sowing rows.

7. Use of a keratin hydrolyzate according to the preceding claim in which the hydrolyzate is used in admixture with the seeds a quantity ranging from 1000 g to 2000 g of active hydrolysate per 1000 kg of seeds or applied to seeds placed in seed rows in a quantity of 1500 g of active hydrolysate per 10000 m2 of planted area, more particularly per 10000 m2 of seed rows.

8. Use of a keratin hydrolyzate according to any one of the preceding claims, characterized in that it is prepared from an animal keratin material, preferably from poultry, according to a preparation process comprising at least one step of acid hydrolysis using a strong acid chosen from hydrochloric, phosphoric and sulfuric acids, preferably hydrochloric acid.

9. Use of a keratin hydrolyzate according to any one of the preceding claims, characterized in that it is prepared from an animal keratin material, preferably from poultry, according to a preparation process comprising at least the following steps, in this order: - subjecting the keratin material to at least one acid hydrolysis under conditions capable of obtaining a hydrolyzate comprising at least 88% by weight of free amino acids relative to the total weight of the amino acids of the hydrolyzate, the remainder of the amino acids of the hydrolyzate being in the form of peptides having a molecular mass less than or equal to 800 Dalton, -preferably extracting the tyrosine and cystine from said hydrolyzate, preferably by means of a base; -optionally drying it.

10. Use according to the preceding claim in which the acid hydrolysis is carried out for a period ranging from 1 hour to 8 hours, preferably ranging from 6 to 7 hours at a temperature ranging from 100 to 115°C, preferably ranging from 110 to 115°C.

11. Use according to one of claims 9 or 10 in which the acid hydrolysis is carried out in two stages: - a first hydrolysis carried out at a temperature ranging from 60 to 80°C for a period ranging from 4 to 5 hours then - a second hydrolysis carried out at a temperature ranging from 100 to 115°C for a period ranging from 5 to 7 hours, the two hydrolyses being able to be carried out without an intermediate pause step or by carrying out an intermediate pause step of between 1 hour and 7 days.

12. Use according to any one of claims 9 to 11 wherein tyrosine and cystine are extracted from said hydrolyzate and the liquid phase obtained after the extraction of cystine and tyrosine is desalted.

13. Use of a keratin hydrolyzate according to any one of the preceding claims for increasing root biomass.

14. Use of a keratin hydrolyzate according to any one of claims 1 to 13 for improving plant emergence, crop establishment, growth and leaf precocity.

15. Use of a keratin hydrolyzate according to any one of claims 1 to 13 to accelerate the emergence of plants and in particular to accelerate the growth rate up to the 6 to 8 leaf stage.

16. Use of a keratin hydrolyzate according to any one of claims 1 to 13 with at least one agent chosen from phytopharmaceutical products, biocontrol agents, plant biostimulants, products based on microorganisms, in particular as a coating.