Method for purifying a target molecule from an aqueous liquid such as fermentation broth

Abstract

The current invention relates to a method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a solvent-impregnated resin comprising one or more (macro)porous resins impregnated with an extractant, said resin has a polymeric backbone and comprises beads with a particle size of between 100 µm and 2000 µm, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecules and said aqueous solution, and recovering said target molecule from said resin.

Description

[0001] METHOD FOR PURIFYING A TARGET MOLECULE FROM AN AQUEOUS LIQUID SUCH AS FERMENTATION BROTH

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to the field of purification and separation technologies, specifically to the use of solvent-impregnated resins (SIRs) for the extraction and recovery of target molecules from aqueous solutions such as fermentation broths or processed liquids thereof. The invention also includes the design and application of these resins in biomanufacturing processes, providing an efficient, cost-effective, and environmentally friendly alternative to traditional liquid-liquid extraction methods.

[0004] BACKGROUND

[0005] In the field of biomanufacturing, the purification of target molecules from aqueous solutions such as fermentation broths is a critical yet challenging step. Traditional purification methods, including liquid-liquid extraction and ion exchange adsorption, often face significant limitations. Liquid-liquid extraction can lead to issues such as emulsion formation and third-phase formation, which complicate the separation process and reduce efficiency. Moreover, these methods typically involve the use of large volumes of organic solvents, which are costly and pose environmental concerns due to their hazardous nature and the generation of waste streams. These challenges contribute to high operational costs, increased chemical consumption, and substantial waste generation, making the need for more efficient, cost-effective, and environmentally friendly purification technologies paramount in the biomanufacturing industry.

[0006] CN 116899535 describes a method for synthesizing an extraction adsorption resin using ionic liquids. The resin is created by combining an imidazolium-based ionic liquid with an anion exchange resin using a solvent impregnation technique. CN '535 describes the use of an ion exchange resin, which is expensive due to a complex manufacturing process.

[0007] The need for a more efficient and cost-effective separation system is driven by the complexity of modern industrial processes. Traditional methods are often limited by their specificity, high operational costs, and waste generation. Industries require flexible systems that can handle various target molecules, from organic acids to metals, across different feed streams. Additionally, these systems promote environmental sustainability by minimizing chemical use and waste, providing a versatile solution for multiple industries.

[0008] Solvent-impregnated resins (SIRs) are used for the extraction of phenol in Burghoff et al., 2009 and van den Berg et al., 2008, of citric acid in Ruey-Shin et al., 1995, of butanol in Tippkotter et al., 2020, and of acetic acid in CN116899535. However, these methods do not report on salts co -extraction, which are often encountered in waste and fermentation streams and pose contamination issues. Moreover, these reports do not use resins with high pore volume, which are important for a high extraction yield. There is a need for methods that solve at least some of these problems.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention relates to a method for purifying target molecules according to claim 1. Specific embodiments are disclosed in claims 2 to 21.

[0011] The invention aims to provide a more efficient and cost-effective purification system by combining solvent-impregnated resins (SIRs) with selective extraction techniques. One of the key advantages is the high surface area of the macroporous beads, which allows for enhanced adsorption capacity. This increased surface area facilitates more effective interaction between the target molecules and the extractant, improving the overall extraction efficiency. Moreover, the optimized pore volume ensures that the active sites of the resin are fully utilized, further enhancing the purification process and reducing the amount of resin required, leading to cost savings.

[0012] Additionally, the use of durable materials increases the lifespan of the system, reducing the frequency of resin replacement. These resins are chemically resistant and thermally stable, allowing them to operate under harsh conditions without significant degradation. This durability not only lowers maintenance costs but also improves the sustainability of the process by minimizing waste and resource consumption. Overall, the invention delivers a more streamlined, reliable, and environmentally friendly solution for industrial-scale purification applications.

[0013] The invention is exemplified in the following embodiments. In an embodiment, the invention comprises a method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a solvent-impregnated resin comprising one or more (macro)porous resins impregnated with an extractant, said resin has a polymeric backbone and comprises beads with a particle size between 100 pm and 2000 pm, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecule and said aqueous solution, and recovering said target molecules from said resin.

[0014] In an embodiment, the resin has a surface area between 500 m2 / g and 2000 m2 / g.

[0015] In an embodiment, said beads have a pore volume between 0.3 mL / g and 3 mL / g. In an embodiment, said resin comprises a water retention between 50% to 90%, preferably between 60% and 75%.

[0016] In an embodiment, said resin is a styrene-divinylbenzene-based resin, an aliphatic polymer-based resin, a methacrylate resin, a phenolic resin, a polysulfone-based resin, a polyethersulfone-based resin, an aromatic polymer-based resin, or a combination thereof.

[0017] In an embodiment, the amount of extractant impregnated into the resin is between 1 g extractant per g dry resin and 5 g extractant per g dry resin.

[0018] In an embodiment, said target molecule comprises at least one or more groups selected from a hydroxyl group, a carboxyl group, an amine group, a phosphate group, dissociated forms thereof or a combination thereof.

[0019] In an embodiment, said target molecule is an acid or an alcohol, preferably an organic acid.

[0020] In an embodiment, said extractant has a water solubility of maximally 1 g / L.

[0021] In an embodiment, said extractant has a boiling point higher than 80 °C, preferably higher than 100 °C.

[0022] In an embodiment, said extractant is an amine, a phosphorous compound or an ionic liquid. In an embodiment, said extractant is chosen from tricotylamine, trialkylphosphine oxides, tributyl phosphate, or an ionic liquid selected from the group consisting of phosphonium-based ionic liquids, ammonium-based ionic liquids, and imidazolium- based ionic liquids.

[0023] In an embodiment, said target molecule is eluted from the resin by adding an alkaline solution to said resin, distillation or back extraction with alcohols.

[0024] In an embodiment, said target molecule is eluted from the resin by adding a volatile base to said resin, wherein the volatile base is preferably trimethylamine, propylamine or butylamine.

[0025] In an embodiment, the aqueous solution is a fermentation broth containing the target molecule.

[0026] In an embodiment, the separation of the resin from the aqueous solution is performed in a fixed-bed column or a fluidized bed system.

[0027] In an embodiment, a purification resin is impregnated with an extractant, wherein said resin is a (macro)porous resin having a polymeric backbone comprising beads with a particle size of between 100 pm and 2000 pm, said resin is a styrene- divinylbenzene-based resin, an aliphatic polymer-based resin, a methacrylate resin, a phenolic resin, a polysulfone-based resin, a polyethersulfone-based resin, an aromatic polymer-based resin, or a combination thereof and wherein said extractant is an amine, a phosphorous compound or an ionic liquid, wherein the amount extractant impregnated into the resin is between 1 g extractant per g dry resin and 5 g extractant per g dry resin.

[0028] DESCRIPTION OF FIGURES

[0029] Figure 1. Effect of impregnating resins with the ionic liquid (IL) CYPHOS IL-104 at a ratio of 1.0 and 2.0 gcYPHos n-104 / g native resin- The pooled mean extraction capacities of 10 different resins is presented with the corresponding standard error. One sided t-tests were performed to compare the groups with each other and assess significance. The sample size (n) varied between 47 and 33 as indicated for each bar. Figure 2. Extraction capacity of 10 macroporous adsorption resins to extract succinic acid, impregnated with 1.0 or 2.0 QCYPHOS n-104 / g native resin . Mean values of independent replicates (n>3) are presented with corresponding standard deviations.

[0030] Figure 3. Extraction capacity for various platform chemicals using the resin AMBERLITE XAD 1600N impregnated with 2.7 gcYPHos n-104 / g native resin . Mean values of independent triplicates are presented with corresponding standard deviations.

[0031] Figure 4. Influence of pH on the extraction capacity of solvent-impregnated resins prepared by impregnating AMBERLITE XAD 1600N with different extractants.

[0032] Figure 5. Effect of added phosphate salts on acetic-acid extraction using CYTOP 503-impregnated AMBERLITE XAD 1600N.

[0033] DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention concerns a method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a solvent-impregnated resin comprising one or more (macro)porous resins impregnated with an extractant.

[0035] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0036] As used herein, the following terms have the following meanings:

[0037] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0038] "About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier about" refers is itself also specifically disclosed.

[0039] "Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0040] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0041] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0042] The expression "% by weight", "weight percent", "%wt" or "wt%", here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation.

[0043] Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.

[0044] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0045] The term "solvent-impregnated resin", "SIR", or "resin" refers in the present invention to a type of resin that is to be impregnated with a specific extractant. The resin typically has a porous structure that allows the extractant to be adsorbed and retained within its matrix. The resin's polymeric backbone provides structural integrity and supports the extractant during the purification process.

[0046] By the term "(macro)porous resins" is meant in the present invention resins that contain pores with varying sizes, including macropores (pores larger than 50 nm in diameter) and micropores (pores smaller than 2 nm in diameter). These pores facilitate the interaction between the target molecules and the extractant. In the context of this invention, "resins" and "beads" are synonymous and are interchangeably used in this text without a difference in meaning.

[0047] The term "extractant" refers to a substance impregnated within the resin that selectively interacts with the target molecule to form a complex. The extractant is typically water-insoluble and has a boiling point higher than 80°C, preferably higher than 100°C. Examples of extractants include amines, phosphorous compounds, and ionic liquids.

[0048] By the term "target molecule" is meant in the present invention a specific molecule intended to be purified from an aqueous solution. The term "aqueous solution" refers to any water-based solution that contains the target molecule. This includes fermentation broths or processed liquids derived from fermentation processes.

[0049] By the term "particle size" is meant in the present invention the size of the individual resin beads, measured in micrometers (pm). Particle size can be measured via laser diffraction or dynamic light scattering.

[0050] In a first aspect, the present invention relates to a method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a solvent-impregnated resin comprising one or more (macro)porous resins impregnated with an extractant, said resin has a polymeric backbone and comprises beads with a particle size between 100 pm and 2000 pm, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said one or more target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecule and said aqueous solution, and recovering said target molecules from said resin. The core of this invention lies in the innovative combination of solvent impregnation and resin adsorption techniques, which together offer numerous advantages over traditional extraction methods. This method reduces costs and improves performance of target molecule purification. A high specificity can be guaranteed while no emulsion or third-phase formation is formed. Furthermore, this method can be performed with industrially available equipment, such as IEX columns.

[0051] Porous resins are widely used in industrial applications for extraction due to their high surface area, tunable pore sizes and chemical stability. These resins act as efficient carriers for extractants which exhibit selective affinity binding to target molecules. This affinity allows for efficient separation and recovery of compounds from complex aqueous mixtures. In large-scale industrial applications, porous resins provide enhanced mass transfer rates and fast extraction kinetics. Furthermore, the resins can be regenerated for reuse, contributing to process sustainability.

[0052] The materials of the resins are preferably chosen for their ability to maintain structural integrity while displaying the correct hydrophobic qualities. In an embodiment, the surface area of the resin is between 500 m2 / g and 2000 m2 / g, preferably between 600 m2 / g and 2000 m2 / g, preferably between 700 m2 / g and 2000 m2 / g, preferably between 800 m2 / g and 2000 m2 / g. In an embodiment, the invention utilizes resins with a pore volume between 0.3 mL / g and 3 mL / g. The use of resins within this range ensures that the available active sites are fully utilized, thereby achieving higher extraction efficiency. The pore volume of the resins is between 0.3 mL / g and 4 mL / g, more preferably between 0.5 mL / g and 3.5 mL / g, more preferably between 1 mL / g and 3 mL / g, more preferably between 1.25 mL / g and 2.75 mL / g, and most preferably between 1.5 mL / g and 2.75 mL / g. This range plays a role in an optimal interaction between the impregnated extractant and the target molecules, facilitating a more effective separation process.

[0053] In an embodiment, the optimized water retention of the resin allows for longer operational cycles between regenerations, reducing downtime and increasing overall process efficiency. This embodiment preferably relates to a resin with a high degree of water retention, which may be achieved by selecting materials with specific hydrophilic properties. The resins preferably comprise a water retention between 50 % to 90 %, preferably between 60% and 75%.

[0054] The optimized water retention of the resin preferably allows for its application in various biomanufacturing processes, where prolonged operational cycles are essential for maintaining high efficiency and reducing downtime. The resin's ability to retain water may also contribute to its stability across multiple extraction cycles, thereby enhancing the overall sustainability and cost-effectiveness of the process.

[0055] In an embodiment, the resins are styrene-divinylbenzene-based resins, aliphatic polymer-based resins, methacrylate resins, phenolic resins, polysulfone-based resins, polyethersulfone-based resins, aromatic polymer-based resins, or a combination thereof. The resins can comprise any material known in the art. In a preferred embodiment, the resins comprise divinylbenzene and / or aliphatic polymers.

[0056] These resins are preferably selected for their robustness and resistance to chemical degradation, which is particularly beneficial in processes involving harsh chemical environments. More preferably, the resins are chosen based on their ability to maintain structural integrity and performance over extended periods of use, thereby reducing the frequency of replacement and maintenance.

[0057] Polysulfone-based resins are preferably characterized by their high thermal stability and resistance to oxidation and hydrolysis. These properties make them suitable for applications where the extraction process may involve elevated temperatures or reactive chemical species. In an embodiment, the polysulfone-based resins exhibit a glass transition temperature in the range of 150°C to 200°C, ensuring that they remain stable and effective under typical operating conditions.

[0058] Phenolic resins, on the other hand, are preferably employed for their excellent mechanical strength and chemical resistance. These resins are more preferably utilized in scenarios where the extraction process involves acidic or basic solutions, as they are known to withstand such conditions without significant degradation. In a further preferred embodiment, the phenolic resins are selected to have a compressive strength of at least 80 MPa, ensuring that they can endure the mechanical stresses encountered during the extraction process.

[0059] In a preferred embodiment, the resins comprise divinylbenzene and / or methacrylate polymers, which provide a high surface area and excellent mechanical stability. These resins are capable of withstanding multiple impregnation and extraction cycles without significant degradation, ensuring long-term usability and cost-effectiveness.

[0060] In an embodiment, the resins used can be commercially available macroporous resins, such as AMBERLITE XAD 7, AMBERLITE XAD 16N, AMBERLITE XAD 1600N, PUROLITE PAD1200, PUROLITE MN202, DIAION HP20, DIAION HP21, DIAION HPO2MGL, DOWEX OPTIPORE L493, Sepabeads SP710. In a preferred embodiment, commercially available resins comprise AMBERLITE XAD 7HP, AMBERLITE XAD 1600N or Sepabeads SP701. The resins are characterized by their high surface area, which provides ample space for the impregnation of extractants and the adsorption of target molecules.

[0061] In an embodiment, only one resin is used. This simplifies the system and ensures consistent interaction between the target molecule and the extractant. This singleresin approach can be preferred for processes where the target molecules have well- defined characteristics, allowing for optimized extraction efficiency and minimal process variability. The use of one resin can reduce operational complexity, lower costs and streamline maintenance. In another embodiment, a combination of two or several different resins can be used. This multi-resin approach can be employed to enhance the overall performance of the purification system. This system allows for greater versatility in capturing a wider range of target molecules, as each resin can be selected for its specific affinity towards different compounds. The combination of resins can for instance be installed in-line, meaning the liquid feed passes through multiple resin beds sequentially, allowing for stepwise purification. This setup is particularly advantageous in cases where the feed solution contains a mix of compounds with varying properties, requiring different resin functionalities to achieve selective extraction and higher overall yield.

[0062] In an embodiment, the solvent-impregnated resins are designed to operate within a specific temperature range that maximizes the performance of the extractants. The operating temperature is preferably between 0°C and 100°C, more preferably between 5°C and 50°C, more preferably between 10°C and 30°C, more preferably between 15°C and 25°C, and most preferably between 15°C and 20°C. This temperature range ensures that the extractants remain in their optimal state for efficient adsorption and desorption of the target molecules.

[0063] In another preferred embodiment, the SIRs demonstrate stability across multiple extraction cycles, making them a cost-effective and sustainable option for industrial applications. The resins are optionally compatible with commercially available equipment such as Ion Exchange Columns (IEX), further simplifying their adoption in various purification processes.

[0064] In an embodiment, the impregnation ratio of the extractant to the resin is optimized to achieve maximum loading efficiency. In an embodiment, the amount of extractant impregnated into the resin is between 1 g extractant per g dry resin and 5 g extractant per g dry resin, more preferably between 1 g extractant per g dry resin and 4 g extractant per g dry resin, more preferably between 1.5 g extractant per g dry resin and 4 g extractant per g dry resin, more preferably between 1.5 g extractant per g dry resin and 3.0 g extractant per g dry resin, more preferably between 2.0 g extractant per g dry resin and 3 g extractant per g dry resin, more preferably between 2.5 g extractant per g dry resin and 2.8 g extractant per g dry resin, and most preferably around 2.7 g extractant per g dry resin. In alternative embodiments, the amount of extractant impregnated into the resin is between 1.8 and 2.7 g extractant per g dry resin, between 1.8 g and 2.6 g extractant per g dry resin, between 1.8 g and 2.5 g extractant per g dry resin, 1.8 g and 2.4 g extractant per g dry resin, 1.8 g and 2.3 g extractant per g dry resin, 1.8 g and 2.2 g extractant per g dry resin, 1.8 g and 2.1 g extractant per g dry resin, 1.8 g and 2 g extractant per g dry resin, or 1.8 g and 1.9 g extractant per g dry resin. In yet other alternative embodiments, the amount of extractant impregnated into the resin is between 1.9 and 2.7 g extractant per g dry resin, between 2 g and 2.7 g extractant per g dry resin, between 2.1 g and 2.7 g extractant per g dry resin, 2.2 g and 2.7 g extractant per g dry resin, 2.3 g and 2.7 g extractant per g dry resin, 2.4 g and 2.7 g extractant per g dry resin, 2.5 g and 2.7 g extractant per g dry resin, or 2.6 g and 2.7 g extractant per g dry resin.

[0065] The extractants are preferably selected from a group of molecules that can form hydrogen bonds or participate in ionic interactions with the target molecule. More specifically, the molecules have functional groups that can interact with acidic or polar groups from the target molecules. More preferably, the extractants may include ionic liquids, amines, or phosphorus compounds, which are known for their high selectivity and minimal solubility in water

[0066] In an embodiment, said extractant is chosen from the group of, but not limited to, amines such as tricotylamine (TOA), phosphorus compounds such as trialkylphosphine oxides (CYTOP 503), or tributyl phosphate (TBP), or an ionic liquid selected from the group consisting of phosphonium-based ionic liquids, ammonium- based ionic liquids, and imidazolium-based ionic liquids. Further examples of possible extractants are ionic liquids with cations, such as imidazolium cations, pyridinium cations, ammonium cations, phosphonium cations, quaternary amines, or anions, such as halides (Cl-, Br), acetate (CHsCOO-), tetrafluoroborate (BF4~), hexafluorophosphate (PFe“), bis(trifluoromethylsulfonyl)imide (Tf2N“). Specific examples are trihexyl(tetradecyl)phosphonium bis(2,4,4- trimethylpentyl)phosphinate (CYPHOS IL-104), trihexyl(tetradecyl)phosphonium chloride (CYPHOS IL-101), methyltrioctylammonium chloride (Aliquat 336), 1-butyl- 3-methylimidazolium hexafluorophosphate (BMIM[PF6]) or trioctylmethylammonium bis(trifluoromethylsulfonyl)imide (OMA[TF2N]). Surprisingly, it was observed that the use of CYTOP 503 results in a low amount of co-extracted salts together with the target molecule. This selective extraction behaviour results in higher purity of the recovered target molecule and prevents resin fouling caused by salt contaminants, which is a common issue in extraction processes reported in the art.

[0067] In an embodiment, commercially available ionic liquid extractants can be used to impregnate the resins, such as CYPHOS IL-104 or Aliquat 336. These extractants are preferably chosen based on their high affinity for the target molecules, thereby enhancing the overall extraction efficiency.

[0068] In a further embodiment, the extractants are amines, which are known for their strong affinity towards the target molecules. Amines, are particularly preferred due to their ability to form strong hydrogen bonds with target molecules such as organic acids, facilitating efficient extraction. The use of amines as extractants is optionally beneficial in processes where a high degree of selectivity is required.

[0069] Phosphorus compounds, such as phosphine oxides, are also possible extractants due to their high extraction efficiency and stability. These compounds are optionally suitable for processes where the target molecules have a high affinity for phosphorus-based extractants. The use of phosphorus compounds can optionally provide a robust and reliable extraction method, ensuring consistent performance across multiple extraction cycles.

[0070] In another embodiment, the extractants used have a high boiling point, above 80 °C, preferably above 100°, such as for example 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, etc. This ensures that the extractants remain within the resins during the extraction process and do not leach out into the aqueous phase. In an embodiment, the extractant has a water solubility of maximally 1 g / L, preferably between 0.001 g / L and 1 g / L, more preferably between 0.01 g / L and 1 g / L, more preferably between 0.1 g / L and 1 g / L, more preferably between 0.5 g / L and 1 g / L.

[0071] The use of high boiling point extractants preferably allows for the continuous operation of the extraction process, minimizing the need for frequent replacement or regeneration of the resins. This results in reduced downtime and operational costs, further improving the overall efficiency of the biomanufacturing process. Moreover, the stability provided by these extractants ensures that the resins maintain their structural integrity and adsorption capacity over multiple extraction cycles, thereby extending their operational lifespan.

[0072] Additionally, the high boiling point extractants are preferably insoluble in water, which prevents their leaching into the aqueous phase during the extraction process. This characteristic is particularly beneficial as it maintains the purity of the extracted target molecules and reduces the risk of contamination. Furthermore, the insolubility of these extractants in water simplifies the separation and recovery of the target compounds, contributing to the overall effectiveness of the extraction method.

[0073] The impregnation procedure for loading extractants onto resins can vary depending on the application, target molecules and resin properties. In an embodiment, the extractant is diluted in a volatile solvent such as acetone or ethanol in a weight / volume ratio between 1 : 1 and 1 :5, preferably between 1 : 1.5 and 1 :3, preferably around 1 :2, and mixed before adding to the resin. The resins are incubated with the extractant / solvent mix for a period of at least 5 hours, preferably at least 4 hours, preferably at least 3 hours, while shaking. After incubation, the resin is dried for 3 hours, preferably 4 hours, preferably 5 hours, preferably 6 hours, preferably 7 hours, preferably 8 hours, etc. to evaporate the solvent, allowing for uniform impregnation.

[0074] In a further embodiment, the impregnation process might involve alternative solvents, such as isopropanol, to dissolve the extractant. These solvents may provide enhanced compatibility with certain resins or target molecules, or they may evaporate more easily, thereby reducing drying time. The use of different solvents could also influence the efficiency of the extractant loading based on solubility or interaction with the resin.

[0075] In an embodiment, the target molecule can form hydrogen bonds or participate in ionic interactions, more specifically having polar functional groups capable of donating or accepting hydrogen bonds with complementary groups. In an embodiment, the target molecule comprises at least one or more groups selected from a hydroxyl group, a carboxyl group, an amine group, a phosphate group or a combination thereof. In a preferred embodiment, the target molecule is an acid or an alcohol, preferably an organic acid. Examples of possible target molecules comprise, but are not limited to, levulinic acid, lactic acid, succinic acid, acetic acid, adipic acid, malic acid, muconic acid, protocatechuic acid, amino acids and / or 1,3- butanediol.

[0076] The pH of the solution is preferably maintained within a range that ensures the stability of the extractant, target molecule and the resin. In a further preferred embodiment, the pH of the aqueous solution is maintained between 0 and 10, more preferably between 1 and 9, more preferably between 2 and 8, more preferably between 3 and 7, more preferably between 3 and 5 and most preferably between 3 and 4. This pH range enhances the selectivity of the extractant for the target molecules, reducing the co-extraction of impurities and improving the purity of the recovered product.

[0077] In an embodiment, the pH of the aqueous solution is under 7. In embodiments, said pH is under 6.5, 6, 5.5, 5, 4.5, 4, 3.5, 3, 2.5 or 2. Surprisingly, the method as disclosed herein yields very high extraction rates when the pH is 7 or lower. Very high yields have been observed when the pH is as low as 2.5, especially for the extractions of acids. In an embodiment, the method may be applied to the in situ removal of target molecules such as organic acids from fermentation broths. This application is particularly advantageous in biomanufacturing processes, where the selective purification of desired target molecules such as organic acids can enhance the efficiency and yield of the overall process. The use of SIRs in this context allows for the continuous extraction of the target molecules, reducing the need for additional purification steps and minimizing the production of waste.

[0078] In another embodiment, the method may be applied in columns in order to purify the target molecule in a batch or continuous flow system. In batch extraction, the entire solution containing the target molecule is processed in discrete batches. The mixture is removed from the production system, such as a bioreactor or fermenter, and the desired molecules are extracted in a separate vessel, such as a column. In a continuous flow system, the liquid medium involves ongoing movement through the purification process. Herein, a liquid stream such as a fermentation broth flows from its production vessel, such as a bioreactor, into one or multiple columns wherein the extraction resins are present. In a preferred embodiment, the method is a continuous flow system.

[0079] In an embodiment, such a column can be installed in-line with the aqueous solution or it can be in a separate installation. Between the outlet of a vessel containing the aqueous solution and the inlet of the column with resins, other columns or vessels could be present for various processing steps.

[0080] In a further embodiment, the process is adapted for continuous operation with an integrated resin regeneration system that allows for simultaneous extraction and elution. This embodiment could involve rotating resin beds or a dual-column setup where one column undergoes regeneration while the other is actively used for extraction. This dual system utilizes a combination of heat and chemical wash steps to ensure complete desorption of target molecules, further extending resin lifespan and reducing operational costs.

[0081] In an embodiment, the separation of the resin from the aqueous solution is performed in a fixed-bed column or a fluidized bed system, both of which offer distinct advantages. In a fixed-bed column, the resin is packed tightly, allowing the aqueous solution to pass through it at a controlled rate, thereby facilitating efficient interaction between the liquid and the resin. This method is ideal for processes requiring precise control and minimal resin movement. On the other hand, a fluidized bed system suspends the resin particles within the liquid, allowing for greater surface area contact and enhanced mass transfer between the resin and the aqueous solution. This dynamic system is often preferred for faster separations and when handling large volumes of liquid, as the fluidized particles reduce the likelihood of clogging and improve the overall efficiency of the separation process.

[0082] In an embodiment, the liquid containing the target molecule can undergo one or multiple processing steps before the extraction of said target molecule. These steps are employed to prepare the solution for optimal resin performance and enhance the effectiveness of the extraction, while preventing resin fouling. In this case, said aqueous solution is a processed liquid that can be used for the target molecule extraction. Said processing steps can be chosen from the group of, but are not limited to filtration techniques such as microfiltration, ultrafiltration, nanofiltration, and depth filtration; centrifugation methods including batch centrifugation, continuous centrifugation, and ultracentrifugation; clarification processes like precipitation and sedimentation; pH adjustment to optimize conditions for resin interaction; thermal treatments such as pasteurization, sterilization, cooling, and heating; solvent addition or dilution to dissolve target molecules or standardize concentration; cell lysis via mechanical, chemical, or sonication methods; concentration techniques like evaporation and reverse osmosis; buffer exchange using dialysis or diafiltration; enzymatic treatments like hydrolysis or enzyme deactivation; defoaming or degassing to reduce gas or foam interference; crystallization to isolate impurities or target compounds; adsorption / desorption pretreatments using activated carbon or ion-exchange materials; sterilization or filtration of air / gas in pressurized systems; settling using flocculants or coagulants; hydrophobic partitioning to remove non-polar compounds; membrane processes like dialysis and electrodialysis; flotation for separating solids or impurities via gas bubbles; emulsification / de-emulsification for creating or breaking emulsions; and pre-chromatographic separation techniques before resin-based purification.

[0083] In an embodiment, the method can be applied across various scales, ranging from small-scale laboratory setups to large-scale industrial environments, making it versatile for different stages of development and production. On a small scale, the method may be utilized in laboratory conditions for research, process optimization, or pilot studies. These setups may involve bioreactors or fermenters with volumes of typically ranging a few liters. Such smaller volumes are ideal for controlled experiments and testing the effectiveness of the method before scaling up. For industrial applications, the method can be employed in larger bioreactors or fermenters with volumes ranging from 5 L to 1 000 000 L, preferably 100 L to 1 000 000 L, more preferably 1 000 L to 1 000 000 L, more preferably 10 000 L to 1 000 000 L. This flexibility in scale allows the method to be integrated into high-volume production systems, such as those used in large-scale fermentation processes, pharmaceutical manufacturing and biotechnology.

[0084] According to an embodiment, the process is a batch process and the contact time between the aqueous solution and the resins is preferably between 5 minutes and 2 hours, more preferably between 10 minutes and 1.5 hours, more preferably between 15 minutes and 1 hour, more preferably between 20 minutes and 45 minutes, and most preferably between 25 minutes and 35 minutes. This contact time ensures sufficient interaction for effective extraction while minimizing the overall process time. In a preferred embodiment, the process is a continuous process and the contact time between the aqueous solution and the resins is preferably as high as possible. Said contact time is minimally 1 bed volumes per hour (BV / h), preferably minimally 2 BV / h, minimally maximally 3 BV / h, preferably minimally 4 BV / h, preferably minimally 5 BV / h, preferably minimally 6 BV / h, preferably minimally 7 BV / h, preferably minimally 8 BV / h, preferably minimally 9 BV / h, preferably 10 BV / h.

[0085] In an embodiment, the ratio of the volume of the aqueous solution to the weight of the resins in a batch process is between 1: 1 and 10: 1, more preferably between 2: 1 and 8: 1, more preferably between 3: 1 and 6: 1, more preferably between 4: 1 and 5: 1, and most preferably between 4.5: 1 and 5: 1. This ratio ensures an adequate amount of SIRs is available to interact with the target molecules, maximizing the extraction efficiency.

[0086] The aqueous solution from which the target molecules are extracted can take several forms, such as waste streams or fermentation broths or processed liquids thereof. In an embodiment, this solution may include, but are not limited to, industrial effluents, process water streams or side streams generated during the production of biofuels, chemicals and / or pharmaceuticals. For example, in biomanufacturing processes, the aqueous solution could be the spent medium following microbial fermentation, containing organic acids or other valuable byproducts. Said aqueous solution can also be a stream containing biocatalytic conversion products.

[0087] In a further embodiment, the solution could originate from the food and beverage industry, such as a sugar-rich liquid or protein-rich extract that requires purification. In wastewater treatment, the aqueous solution may consist of contaminated water streams containing pollutants such as heavy metals, dyes or organic solvents, where selective extraction is essential for environmental safety. The aqueous solution could come from petrochemical processes, where hydrocarbons or byproducts need to be removed or recovered. Additionally, mining industries may present aqueous solutions in the form of leachates, from which valuable metals such as copper, nickel or lithium can be selectively separated. In a preferred embodiment, the aqueous solution is a fermentation broth or a processed liquid thereof.

[0088] In an embodiment, the method for the extraction and recovery of target molecules such as organic acids using solvent impregnated resins involves the use of an alkaline solution or a volatile base for elution, distillation or back extraction with alcohols. The elution with an alkaline solution simplifies the overall process by enabling selective and efficient recovery of the target molecule. The alkaline solution, which may preferably be a sodium hydroxide solution, interacts with the impregnated resin to release the adsorbed target molecule. This interaction is facilitated through a pH- driven mechanism where the alkaline environment disrupts the ionic interactions or hydrogen bonds between the extractant and the target molecule. Addition of a volatile base has the same effect. In an embodiment, trimethylamine (TMA), propylamine or butylamine is added for elution. In a preferred embodiment, TMA is added.

[0089] In another embodiment, the method for extraction and recovery may involve distillation or back extraction with alcohols. These methods offer alternative approaches for selectively recovering the target molecule from the resin. Distillation leverages differences in volatility between the extractant and the target molecule, allowing for the separation of the target compound through vaporization and condensation. This method is particularly effective for molecules with distinct boiling points. Back extraction with alcohols on the other hand, involves contacting the resin with an alcohol solution, which disrupts the interactions between the extractant and the target molecule, facilitating desorption. The use of alcohols as a back-extraction solvent is advantageous due to their ability to selectively dissolve the target molecule without contaminating the aqueous phase, simplifying the separation and recovery process.

[0090] In a further embodiment, the elution method can be chosen from the group of, but not limited to, acidic elution, solvent desorption, steam stripping, thermal desorption, supercritical fluid extraction, organic solvent wash, pH swing elution, salt solution elution, surfactant-assisted desorption, microwave-assisted desorption, ultrasonic-assisted desorption, pressure swing elution. In an embodiment, multiple elution methods can be applied in subsequent steps. The concentration of the alkaline solution or volatile base is preferably at least 1 M, more preferably at least 2 M, more preferably at least 5 M, more preferably at least 7 M, more preferably at least 10 M, more preferably at least 15 M, more preferably at least 20 M. The choice of concentration is critical to ensure that the elution process is both efficient and selective, minimizing the co-elution of impurities while maximizing the recovery of the target organic acid.

[0091] The use of an alkaline solution for elution offers several advantages, including the ability to regenerate the resin for multiple cycles of extraction and elution, thereby enhancing the sustainability and cost-effectiveness of the process. Additionally, the alkaline solution can be easily neutralized and disposed of. The simplicity and efficiency of this approach make it highly suitable for integration into existing biomanufacturing workflows, providing a robust and scalable solution for the recovery of valuable target molecules. The use of a volatile base, such as TMA, can easily be evaporated after the elution. Subsequently, the base can be re-used and a neutralization step can be omitted, leading to less needed resources and less waste since no salts will be formed. Overall the use of a volatile base is an efficient and ecologically justified option.

[0092] In a further embodiment, the temperature of the elution process of distillation is maintained between 20°C and 200°C, more preferably between 25°C and 200°C, more preferably between 30°C and 200°C, more preferably between 50°C and 200°C, and most preferably between 100°C and 200 °C. The temperature range is chosen to optimize the kinetics of the elution process, ensuring that the interaction between the alkaline solution and the resin is efficient without causing thermal degradation of the target molecules or the resin itself.

[0093] The method optionally includes a regeneration step for the resins, where the spent resins are washed with a suitable regenerant, such as a dilute acid or base solution, to remove the adsorbed target molecules and prepare the resins for reuse. This regeneration step is preferably conducted at a temperature between 20 and 80°C, more preferably between 30 and 70°C, more preferably between 40 and 60°C, and most preferably between 50 and 55°C. The use of a regenerant with a pH between 1 and 12, more preferably between 2 and 11, more preferably between 3 and 10, more preferably between 4 and 9, and most preferably between 5 and 8, ensures effective desorption of the target molecules without damaging the resin structure. This regeneration process allows the SIRs to be reused for multiple extraction cycles, reducing the overall cost and environmental impact of the extraction process. The streamlined process includes fewer steps compared to traditional liquid-liquid extraction methods. By using SIRs, the need for multiple phase separation steps is reduced, as the extractant is immobilized within the resin matrix. This allows for a more efficient and rapid extraction process, which can optionally lead to shorter production times and increased throughput.

[0094] In another embodiment, the method reduces waste production and chemical consumption, making the process more environmentally friendly. This is optionally achieved by the easy regeneration of the resins, which allows for multiple cycles of extraction without significant loss of efficiency.

[0095] The method's versatility extends to various industrial applications, including the recovery of valuable compounds such as alcohols, amino acids, and rare earth metals from aqueous streams, such as waste streams or fermentation broths. It can also be used in the purification of organic acids, dyes, and pharmaceutical compounds, as well as in water treatment for the removal of heavy metals and pollutants. By adjusting the choice of extractants, resins, and operating conditions, the method can be tailored to target specific molecules, providing a highly flexible and efficient solution for diverse separation challenges. In petrochemical industries, it could aid in separating hydrocarbons from aqueous mixtures, while in the food and beverage industry, it can be applied for the extraction of flavors, sugars, and proteins from complex feed solutions. The method is adaptable for continuous or batch processes, enabling its integration into large-scale production lines. Furthermore, in the mining industry, it can be employed for the selective extraction of valuable metals such as copper, nickel, and lithium from ore leachates, enhancing the overall recovery process and minimizing environmental impact.

[0096] In a specific embodiment, the disclosure relates to a method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a styrene- divinylbenzene-based resin impregnated with between 1.8 g extractant per g dry resin and 2.7 g extractant per g dry resin, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecule and said aqueous solution, and recovering said target molecules from said resin, wherein the extractant is a phosphorus compound. In a preferred embodiment, the resin is Amberlite XAD 1600N._The phosphorus compound is selected from trialkylphosphine oxide or tributyl phosphate, preferably trialkylphosphine oxide. The target molecule is selected from , levulinic acid, lactic acid, succinic acid, acetic acid, adipic acid, malic acid, muconic acid, protocatechuic acid, 1,3-butanediol, an amino acid or combinations thereof. The pH of the aqueous solution is lower than 7, as disclosed in any of the previous embodiments. This specific embodiment of the method may be combined with any other features disclosed in the previous embodiments, without departing from the scope of the invention.

[0097] The inventors observed that by using this method very high yields of target molecules are purified and moreover a low amount of salts is co-extracted together with the target molecule. This selective extraction behaviour results in higher purity of the recovered target molecule and prevents resin fouling caused by salt contaminants, which is a common issue in extraction processes reported in the art. The selection of the resin, extractant and their ratio contribute to these effects.

[0098] In a second aspect, the present invention relates to a purification resin impregnated with an extractant, wherein said resin is a (macro)porous resin having a polymeric backbone comprising resins with a particle size of between 100 pm and 2000 pm, said resin is a styrene-divinylbenzene-based resin, an aliphatic polymer-based resin, a methacrylate resin, a phenolic resin, a polysulfone-based resin, a polyethersulfone- based resin, an aromatic polymer-based resin, or a combination thereof and wherein said extractant is an amine, a phosphorous compound or an ionic liquid, wherein the amount extractant impregnated into the resin is between 1 g extractant per g resin and 5 g extractant per g resin. Said resin is an embodiment of the resin described as above.

[0099] In a further embodiment, the resins exhibit enhanced resistance to both chemical and mechanical degradation. This includes resistance to common industrial solvents, such as alcohols, acetone or toluene, ensuring the resins can withstand the harsh environments often found in biomanufacturing processes. In an embodiment, the resins demonstrate resistance to fouling caused by high organic loads, such as proteins, lipids or other biopolymers present in liquid feed streams.

[0100] In an embodiment, the resins can be impregnated with nanoparticles, such as silica, titanium or magnetic nanoparticles, to enhance surface area and increase adsorption efficiency. The inclusion of magnetic nanoparticles can allow for magnetic separation of the resins after extraction, making the process faster and more energy-efficient. The dual-phase extractants could include a hydrophobic solvent, such as toluene, and a hydrophilic solvent, such as an ionic liquid, both impregnated within the same resin. In an embodiment, the solvent-impregnated resins are adapted for use in gas-liquid extraction processes, where the target molecule is captured from a gas stream that has been bubbled through a liquid medium. This could be used for the selective removal of volatile organic compounds or greenhouse gases such as CO2 from industrial emissions. The resin's porosity and surface area can be tailored to maximize gas-liquid interaction, and the extractants used would be capable of selectively capturing gas-phase molecules from the liquid interface.

[0101] In an embodiment, an industrial plant designed for large-scale biomechanical production comprises a fermentation tank or bioreactor with a capacity tailored to the needs of high-volume feedstock conversion. The bioreactor, which may range in volume from minimally 100 L, preferably minimally 1000 L, more preferably minimally 10000 L, more preferably minimally 100000 L, most preferably minimally 1000000 L, facilitates the growth of microorganisms or enzymes to convert the feedstock into target molecules, such as organic acids, proteins or biofuels. Upon completion of the fermentation process, the resulting broth containing the target molecules can be transferred to a downstream processing unit for further refinement. Here, the process incorporates a purification system that utilizes solvent- impregnated resins which can be impregnated with specific extractants as describes above. The solvent-impregnated resins used in an embodiment are characterized as described above. Between the bioreactor and the purification system, other columns can be added for processing steps such as centrifugation, filtration, etc.

[0102] During operation, the fermentation broth can be brought into liquid contact with the resin, allowing target molecules to interact selectively with the impregnated extractant through affinity mechanisms, such as ionic interactions or hydrogen bonding. The amount of extractant impregnated within the resin can vary between 1 g and 5 g per g of dry resin, depending on the specific process requirements. The extractants may include compounds such as amines, phosphorous compounds, like trialkylphosphine oxides, or ionic liquids, like or ammonium-based ionic liquids, that exhibit low water solubility and high thermal stability.

[0103] EXAMPLES

[0104] The present invention will now be further exemplified with reference to the following examples. The present invention is in no way limited to the given examples or to the embodiments presented in the figures. Example 1 : Lab scale

[0105] To impregnate the resins, the desired amount of ionic liquid CYPHOS IL-104 was mixed with acetone in ratio of 1 :2 (w / V). Then, the native resin was added to the mixture and left shaking for 3 h at room temperature. The acetone was subsequently evaporated by increasing the temperature overnight to 60°C. If required, the impregnated resin was contacted with NaOH (IM) in a ratio of 1 :25 (w / V) and washed with water until the pH was neutral. The amount of ionic liquid (IL) loaded on the native resin is referred to as impregnation ratio and is calculated based as a ratio of the mass of native resin and the mass of the IL that was loaded on the resin.

[0106] For extraction of organic acids, aqueous solutions of 50 ± 1.7 g / L were prepared in demineralized water. As adipic acid has a lower solubility in water, a solution of 19 g / L was used. The initial pH values were below <2.5, and hence below the pKa values of the acids ensuring that the majority of the acid is present in its undissociated form. Solutions of 1,3-butanediol were prepare similarly with a concentration of 50 g / L, whereas the initial pH was 4.39.

[0107] For screening and optimization trials, 0.1 g of impregnated resin was mixed with 2.5 mL of aqueous solutions in 5 mL Eppendorf tubes. After shaking in a ThermoMixer (Eppendorf, Hamburg, Germany) at 900 rpm for 3 h, the aqueous solution was separated by filtration and analyzed by HPLC. The extraction capacity of the resin (q) is expressed as amount of target product before (m0) and after (mf) extraction per gram of native resin (mnr).

[0108] For back extraction at lab scale, 2.5 mL of IM NaOH was added to the loaded resin, shaken for 2h and subsequently removed and by filtration. The eluted target compound in the basic solution was analysed by HPLC. If the resin was recycled, the resin after back extraction was washed with two times 5 mL of water to remove traces of NaOH before re-usage.

[0109] Initially, a selection of 10 macroporous adsorption resins were impregnated with CYPHOS IL-104 at impregnation ratios of 0.0, 1.0, and 2.0 g CYPHOS iL-104 / g native resin and evaluated for their performance to extract succinic acid from aqueous solution (50 g / L) (Table 1). The impregnation of all tested resins led to a significant improvement of extraction capacity for succinic acid at both impregnation ratios (Fig. 1). While for non-impregnated resins, the average extraction performance amounts to 39.2 mgsA / gnative resin, this increased to 150.8 mg SA / 9 native resin and 228.5 mgSA / gnative resin for an impregnation ratio of 1.0 gcYPHos n-104 / gnative resin and 2.0 gcYPHos n-104 / g native resin, respectively, resulting in an enhancement of succinic acid extraction by 582%.

[0110] Table 1. Specification of resins used in this study. In the following sections, the resins are abbreviated as marked in bold, ^ivynilbenzene _ c , Particle Pore Particle

[0111] Name Matrix area ( ,7 / . diameter diameter density

[0112] 1m2 / / gy)' (,pm .) ( ,A) ( ,Q / ,m ,L)

[0113] AMBERLITE XAD 7HPc™sshnked52o 430-690 550 1.06-1.08 aliphatic polymer

[0114] AMBERLITE XAD 16N crosslinked DVB1940 560-710 150 1.015-1.025

[0115] AMBERLITE XAD 1600N crosslinked DVB 800 400 ±50 150 1.015-1.025

[0116] PUROLITE PAD1200 crosslinked DVB 700 300-1200 240 1.02

[0117] PUROLITE MN202 crosslinked DVB 950 300-1200 220 1.04

[0118] DIAION HP20 crosslinked DVB 590 250±25 290 1.01

[0119] DIAION HP21 crosslinked DVB 640 250±25 110 1.01

[0120] DIAION HP2MGL ^Spolymer 570 355±3 240 1.09

[0121] DOWEX OPTIPORE L493 crosslinked DVB 1100 297-841 46 0.62

[0122] Sepabeads SP710 crosslinked DVB 1046 250 90 1.01

[0123] Concentrations of succinic acid, 1,3-butanediol, malic acid, adipic acid, acetic acid, levulinic acid, and lactic acid were analyzed using an Agilent 1260 Infinity HPLC with a Metacarb 67 H column (300 x 6.5 mm, connected to a varia 5244GC precolumn). 2.5 mM H2SO4 was used as mobile phase with a flow of 0.8 mL min-1, whereas the column temperature was 40 °C. The compounds were detected by a refractive index detector (RID) and results were processed using Agilent OpenLab CDS.

[0124] The highest extraction capacity at an impregnation ratio of 1.0 gcYPHos n-104 / g native resin was found for the resin XAD 7 reaching a capacity of 192.0 mgsA / gnative resin . Interestingly, the highest performance at an impregnation ratio of 2.0 gcYPHos n- 104 / gnative resin was found for another resin, namely XAD 1600, reaching 370.2 mgsA / gnative resin, which is at 150% higher than the other resins (Fig. 2). The differences are most likely linked to the resin properties. Next to the matrix, which is important to have a high affinity to the IL that is impregnated, the surface area as well as the particle and pore diameter are crucial. Whereas larger particles could be beneficial to hold more ionic liquid, a large surface area is a factor as well to increase the interaction area between matrix and IL to avoid leaching of the extractant. To assess the suitability of the developed resin for other target compounds, the optimized resin, namely AMBERLITE XAD 1600 N impregnated with 2.7 gcYPHos iL- 104 / g native resin was applied to aqueous solutions of the organic acids malic acid, lactic acid, acetic acid, adipic acid, levulinic acid, and succinic acid. Additionally, the secondary alcohol 1,3-butanediol was tested to explore the applicability to other valuable platform chemicals.

[0125] The results indicate that all tested compounds can be extracted using the developed SIR. The extraction capacity varies for the different compounds in dependence of the properties of the product and the affinity to the CYPHOS IL-104 (Fig. 3). For organic acid extraction, the highest capacity was found for succinic acid, reaching 736 mgsA / gnative resin, whereas the one for malic acid was the lowest reaching 490 mgsA / g native resin - The capacity for 1,3-butanediol was 147 mgSA / g native resin - Succinic acid is a dicarboxylic acid with two carboxyl groups that can strongly interact with CYPHOS IL-104. While adipic acid is also a dicarboxylic acid with a higher hydrophobicity due to the longer alkyl chain, which increases its affinity to the hydrophobic IL, the molecular weight is also higher. Malic acid was extracted the least despite its dicarboxylic characteristics, most likely because of its high hydrophilicity which is increased by the additional hydroxy group. 1,3-butandiol can interact through the hydroxy groups with the extractant, however, these interactions are less strong compared to interaction of a carboxyl group, explaining the lower extraction capacity compared to the acids.

[0126] Example 2: Pilot scale

[0127] Pilot-scale extraction was executed in a 20 L, double-jacketed, stirred-tank reactor made from Hastelloy (H.E.L. Group, Princeton, New Jersey, United States). For extraction, 10 L of a 100 g / L aqueous solution of acetic acid was used and mixed with a total of 3384 g of impregnated resin and afterwards drained through an inline sieve to ensure that no resin was lost. For subsequent product removal of acetic acid from the resin, the reactor was heated to a maximum of 155°C by circulation of thermal oil through the double jacket. The vessel was connected to a distillation column, that was cooled at 4°C and a vacuum pump, enabling a vacuum of up to 15 mbar. All aqueous streams were analyzed by HPLC to quantify acetic acid.

[0128] For this extraction, resins were used that comprise polymeric backbone, specifically based on styrene-divinylbenzene, and is engineered with beads ranging in size from 300 pm to 1500 pm. It features a surface area between 500 m2 / g and 2000 m2 / g, enhancing the contact efficiency with target molecules. The pore volume of the resin is between 1 mL / g and 3 mL / g, which facilitates the accommodation of both the extractant and the target molecules within the resin's matrix. Additionally, the resin has a water retention capacity of 50% to 90%, allowing it to maintain hydration while enabling effective molecule capture in aqueous environments.

[0129] Concentrations of succinic acid, 1,3-butanediol, malic acid, adipic acid, acetic acid, levulinic acid, and lactic acid were analyzed using an Agilent 1260 Infinity HPLC with a Metacarb 67 H column (300 x 6.5 mm, connected to a varia 5244GC precolumn). 2.5 mM H2SO4 was used as mobile phase with a flow of 0.8 mL min-1, whereas the column temperature was 40 °C. The compounds were detected by a refractive index detector (RID) and results were processed using Agilent OpenLab CDS.

[0130] One possible application of SIRs is the extraction and concentration of aqueous acetic acid streams, for instance derived from fermentation. These streams are usually low in concentration (10-20%), which requires evaporation or distillation steps to yield usable steps for further valorization. Extraction of acetic acid with SIRs can be an alternative solution to selectively extract acetic acid and removing water. When the acetic acid is bound to the resin, direct distillation from the resin has been described as an option to directly recover purified and concentrated acid.

[0131] This has been evaluated in a 20 L stirred, chemical reactor, where a total of 3.4 kg of impregnated resin has been mixed with 10 L of a 99.6 g / L solution of acetic acid, amounting to an absolute acetic acid amount of 996 g. From this, a total of 369 g of acetic acid was bound to the resin, resulting in extraction capacity of the resin of 409 mgsA / gnative resin. After draining of the remaining aqueous solution of acetic acid through an inline sieve, direct distillation of acetic acid was assessed by heating the mixture to a maximum of 153°C, and a vacuum of 100 mbar inside the reactor. Overall, through distillation, a total acidic acid recovery of 50% was reached, amounting to 185 g of acetic acid.

[0132] Example 3

[0133] A fermentation broth containing acetic acid was purified using an AMBERLITE XAD 1600N resin impregnated with an ammonium-based ionic liquid. The resin resins had a particle size of 350 pm to 450 pm, a surface area of 700 m2 / g, and a pore volume of 1.8 mL / g. The resin was impregnated with 1.5 g extractant per g resin. The broth was passed through a fixed-bed column containing the SIR, and the acetic acid was selectively adsorbed. The resin was separated from the broth, and the acetic acid was eluted using an alkaline solution. This method resulted in an extraction efficiency of 88% and a purity of 94%, demonstrating accelerated processing time and increased capacity utilization.

[0134] Example 4

[0135] To assess the impact of pH on the extraction, various resins were prepared by impregnating AMBERLITE XAD 1600N with the following extractants: Trioctylamine (TOA), CYPHOS IL-104, CYPHOS IL-103, and CYTOP 503. The impregnation ratio varied between 1.8 and 2.6 g extractant / g native resin. These SIRs were evaluated to extract 50 g / L of acetic acid at a pH of 2.5 and at a pH of 7.0.

[0136] The results indicate that the extraction capacity is highly dependent on the pH of the feed solution, where a lower pH (<pKa of the target molecule) is preferred over a higher pH (>pKa of the target molecule) (Figure 4). Indeed, for all tested extractants, the extraction capacity for acetic acid at a low pH ranged from 737.7 mg acetic acid / g native resin for TOA to 367.6 mg acetic acid / g native resin for Aliquat 336. At a higher pH, on the other hand, the extraction capacities were significantly lower, ranging from 241.8 mg acetic acid / g native resin for Aliquat 336 to 56.6 mg acetic acid / g native resin for CYTOP 503.

[0137] Example 5

[0138] To evaluate the influence of salts on the extraction capabilities of SIRs, a feed medium containing 50 g / L of acetic acid with phosphate salts (KH2PO4) was prepared and compared to a medium without added salt. The acetic acid was extracted using SIRs prepared by impregnating CYTOP 503 on AMBERLITE XAD 1600N at a ratio of 2.5 g extractant / g native resin. The results show that the extraction capacity for acetic acid does not significantly change when adding phosphate. Indeed, 426.6 ± 20.1 mg acetic acid / g native resin was extracted without added salts and 418.2 ± 32.3 mg acetic acid / g native resin with added salts. Moreover, a limited amount of phosphate was co-extracted. Indeed, 8.3 ± 2.7 mg phosphate / g native resin was extracted, accounting for less than 2% co-extraction (Figure 5). It is supposed that the present invention is not restricted to any form of realization described previously and that some modifications can be added to the presented example of fabrication without reappraisal of the appended claims. For example, the present invention has been described referring to specific types of resins and extractants, but it is clear that the invention can be applied to other types of resins and extractants for instance or to different target molecules.

[0139] It is clear that the method according to the invention, and its applications, are not limited to the presented examples.

Claims

1. 29CLAIMS1. A method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a solvent-impregnated resin comprising one or more (macro)porous resins impregnated with an extractant, said resin has a polymeric backbone and comprises beads with a particle size between 100 pm and 2000 pm, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecule and said aqueous solution, and recovering said target molecules from said resin.

2. The method according to claim 1, wherein the pH of the aqueous solution is lower than 7.

3. The method according to claims 1 or 2, wherein said resin has a surface area between 500 m2 / g and 2000 m2 / g.

4. The method according to any of the preceding claims, wherein said beads have a pore volume between 0.3 mL / g and 3 mL / g.

5. The method according to any of the preceding claims, wherein said resin comprises a water retention between 50% to 90%, preferably between 60% and 75%.

6. The method according to any of the preceding claims, wherein said resin is a styrene-divinylbenzene-based resin, an aliphatic polymer-based resin, a methacrylate resin, a phenolic resin, a polysulfone-based resin, a polyethersulfone-based resin, an aromatic polymer-based resin, or a combination thereof.

7. The method according to any of the preceding claims, wherein the amount of extractant impregnated into the resin is between 1 g extractant per g dry resin and 5 g extractant per g dry resin.

8. The method according to any of the preceding claims, wherein said target molecule comprises at least one or more groups selected from a hydroxyl group, a carboxyl group, an amine group, a phosphate group, dissociated forms thereof or a combination thereof.

9. The method according to any of the preceding claims, wherein said target molecule is an acid or an alcohol, preferably an organic acid.

10. The method according to any of the preceding claims, wherein said extractant has a water solubility of maximally 1 g / L.3011. The method according to any of the preceding claims, wherein said extractant has a boiling point higher than 80 °C, preferably higher than 100 °C.

12. The method according to any of the preceding claims, wherein said extractant is an amine, a phosphorous compound or an ionic liquid.

13. The method according to any of the preceding claims wherein said extractant is chosen from tricotylamine, trialkylphosphine oxides, tributyl phosphate, or an ionic liquid selected from the group consisting of phosphonium-based ionic liquids, ammonium-based ionic liquids, and imidazolium-based ionic liquids.

14. A method for purifying one or more target molecules from an aqueous solution such as fermentation broth or a processed liquid thereof, said purification step comprises the use of a styrene-divinylbenzene-based resin impregnated with between 1.8 g extractant per g dry resin and 2.7 g extractant per g dry resin, wherein during purification said liquid feed is contacted with said resin, thereby allowing the selective interaction of said target molecules with said extractant to form a complex within the porous resin, subsequently separating said resin containing the target molecule and said aqueous solution, and recovering said target molecules from said resin, wherein the extractant is a phosporous compound.

15. The method of claim 14, wherein the phosporous compound is selected from trialkylphosphine oxide or tributyl phosphate, preferably trialkylphosphine oxide.

16. The method according to any of the claims 14 or 15, wherein the target molecule is selected from , levulinic acid, lactic acid, succinic acid, acetic acid, adipic acid, malic acid, muconic acid, protocatechuic acid, 1,3-butanediol, an amino acid or combinations thereof.

17. The method according to any of the claims claim 14 to 17 wherein the pH of the aqueous solution is lower than 7.

18. The method according to any of the preceding claims, wherein said target molecule is eluted from the resin by adding an alkaline solution to said resin, distillation or back extraction with alcohols.

19. The method according to any of the preceding claims, wherein said target molecule is eluted from the resin by adding a volatile base to said resin, wherein the volatile base is preferably trimethylamine, propylamine or butylamine.

20. The method according to any of the preceding claims, wherein the aqueous solution is a fermentation broth containing the target molecule.

21. The method according to any of the preceding claims, wherein the separation of the resin from the aqueous solution is performed in a fixed-bed column or a fluidized bed system.

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