CN-121990899-A - Method for preparing 3-hydroxybutyric acid by direct crystallization from hydrolysate

CN121990899ACN 121990899 ACN121990899 ACN 121990899ACN-121990899-A

Abstract

The invention provides a method for preparing 3-hydroxybutyric acid by direct crystallization from hydrolysate, belonging to the technical field of biosynthesis. The method comprises the steps of (1) primary crystallization, namely adding a crystallization solvent into a poly (3-hydroxybutyrate) hydrolysate, cooling, crystallizing, performing suction filtration and top washing to obtain a 3-hydroxybutyric acid crude product, and (2) secondary crystallization, namely adding the 3-hydroxybutyric acid crude product into the crystallization solvent, heating, dissolving, cooling, crystallizing, performing suction filtration, top washing and drying to obtain the 3-hydroxybutyric acid. The invention realizes the direct crystallization of the hydrolysis liquid of poly-3-hydroxybutyrate to obtain solid 3-hydroxybutyrate product, has the advantages of high content (more than 98%), high purity (more than 99%), basically no impurity crotonic acid residue (< 0.01%), short production period, low equipment requirement, low raw material cost, simple production operation and the like, is suitable for industrial production, and has good application prospect.

Inventors

ZHANG HAILEI
ZHAO XIAOLONG
ZHANG XIAFEI
MEI JIE
ZHANG BAOXIN
NUERMAIMAITI.KUDABAERDI
ZHOU LU
elimi hot wood ilham
ZHANG FANGFANG
Muyaseer Ablimiti
Malbia Yushufu River

Assignees

伊犁川宁生物技术股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260226

Claims (10)

1. A method for preparing 3-hydroxybutyric acid by direct crystallization from hydrolysate is characterized by comprising the following steps: (1) Primary crystallization, namely adding a crystallization solvent into the poly 3-hydroxybutyrate hydrolysate, cooling for crystallization, and carrying out suction filtration and top washing to obtain a crude product of the 3-hydroxybutyrate; (2) And (3) secondary crystallization, namely adding the 3-hydroxybutyric acid crude product into a crystallization solvent, heating to dissolve, cooling to crystallize, filtering, top washing and drying to obtain the 3-hydroxybutyric acid.
2. The method according to claim 1, wherein in the step (1), the hydrolysis liquid of poly (3-hydroxybutyrate) is a hydrolysis liquid containing 3-hydroxybutyric acid obtained by acidic or basic hydrolysis, neutralization and concentration of poly (3-hydroxybutyrate).
3. The method according to claim 1, wherein in the step (1) and the step (2), the crystallization solvent is independently selected from one or a combination of two or more of C 1 ~C 5 alcohol solvents, C 1 ~C 5 ketone solvents, C 1 ~C 10 ether solvents, C 1 ~C 10 ester solvents and C 1 ~C 5 nitrile solvents.
4. The method according to claim 3, wherein the C 1 ~C 5 alcohol solvent is one or a combination of two or more of methanol, ethanol and isopropanol, and/or the C 1 ~C 5 ketone solvent is one or a combination of two or more of acetone and methyl ethyl ketone, and/or the C 1 ~C 10 ether solvent is one or a combination of two or more of diethyl ether, propyl ether, tetrahydrofuran, isopropyl ether, isobutyl ether and methyl tert-butyl ether, and/or the C 1 ~C 10 ester solvent is one or a combination of two or more of ethyl formate, ethyl acetate and butyl acetate, and/or the C 1 ~C 5 nitrile solvent is acetonitrile. Preferably, in step (1), the crystallization solvent is selected from the group consisting of methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, diethyl ether, propyl ether, tetrahydrofuran, isopropyl ether, isobutyl ether, methyl tertiary butyl ether, ethyl formate, ethyl acetate, butyl acetate, and acetonitrile, and/or, in step (2), the crystallization solvent is selected from the group consisting of methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, diethyl ether, propyl ether, tetrahydrofuran, isopropyl ether, isobutyl ether, methyl tertiary butyl ether, ethyl formate, ethyl acetate, butyl acetate, and acetonitrile; More preferably, in step (1), the crystallization solvent is selected from ethanol, and/or in step (2), the crystallization solvent is selected from ethanol.
5. The method according to claim 1, wherein in the step (1), the cooling crystallization process is divided into two stages, the first stage is cooled to 10 ℃ to-15 ℃ for crystallization, and the second stage is cooled to-5 ℃ to-30 ℃ for crystallization; and/or in the step (1), the method of suction filtration and top washing is to use one or a combination of two or more of C 5 ~C 8 alkane solvent and aromatic hydrocarbon solvent for top washing during suction filtration, and collect filter cakes to obtain a crude 3-hydroxybutyric acid product; Preferably, in the step (1), the cooling crystallization process is divided into two stages, wherein the first stage is cooled to 5 ℃ to-10 ℃ for crystallization, the crystallization time is 1-5 h, and the second stage is cooled to-10 ℃ to-20 ℃ for crystallization, and the crystallization time is 1-10 h; And/or in the step (1), the solvent used for top washing is one or a combination of two or more of n-heptane, 2-methylhexane, n-pentane and n-hexane.
6. The method of claim 1, wherein in the step (2), the method further comprises decolorization between the heating dissolution and the cooling crystallization, wherein the crude product is dissolved and then added with active carbon for decolorization and suction filtration to obtain decolorized solution, and then the temperature is lowered for crystallization.
7. The method according to claim 6, wherein in the step (2), the cooling crystallization process is divided into one or two stages, and when the cooling crystallization process is one stage, the temperature is reduced to 30 ℃ to-10 ℃ for crystallization, and when the cooling crystallization process is two stages, the temperature is reduced to 30 ℃ to 10 ℃ for crystallization, and the temperature is reduced to 10 ℃ to-10 ℃ for crystallization; And/or in the step (2), the method of suction filtration and top washing is to use one or a combination of two or more of C 5 ~C 8 alkane solvent and aromatic hydrocarbon solvent for top washing during suction filtration, collect filter cakes and dry to obtain a crude 3-hydroxybutyric acid product; Preferably, the method comprises the steps of, In the step (2), the cooling crystallization process is divided into one or two stages, when the cooling crystallization process is one stage, the temperature is reduced to 25 ℃ to 0 ℃ for crystallization, the crystallization time is 1 to 5 hours, when the cooling crystallization process is two stages, the temperature is reduced to 25 ℃ to 10 ℃ for crystallization, the crystallization time is 1 to 5 hours, and the temperature is reduced to 10 ℃ to-5 ℃ for crystallization, and the crystallization time is 1 to 5 hours; And/or in the step (2), the solvent used for top washing is one or a combination of two or more of n-heptane, 2-methylhexane, n-pentane, n-hexane and toluene.
8. The method of claim 1, wherein in the step (2), the mother liquor obtained after the secondary crystallization process and suction filtration is concentrated, and then primary crystallization and suction filtration are carried out according to the method provided in the step (1) to obtain a crude product; and/or in the step (2), the mother liquor obtained after the suction filtration is added into the poly 3-hydroxybutyrate hydrolysate in the secondary crystallization process, and then the primary crystallization is carried out according to the method provided in the step (1), and the suction filtration is carried out, so that the crude product is obtained.
9. The method of claim 1, wherein the poly (3-hydroxybutyrate) is selected from the group consisting of poly (3-hydroxybutyrate) racemate, poly (R) -3-hydroxybutyrate, and poly (S) -3-hydroxybutyrate.
10. The method according to any one of claims 1 to 9, wherein the 3-hydroxybutyric acid obtained in the step (2) has a 3-hydroxybutyric acid content of >98% and a purity of >99% and is free of crotonic acid residues; Preferably, the 3-hydroxybutyric acid is selected from one or a combination of two or more of 3-hydroxybutyric acid racemate, (R) -3-hydroxybutyric acid and (S) -3-hydroxybutyric acid.

Description

Method for preparing 3-hydroxybutyric acid by direct crystallization from hydrolysate Technical Field The invention belongs to the technical field of biosynthesis, and particularly relates to a method for preparing 3-hydroxybutyric acid by direct crystallization from hydrolysate. Background 3-Hydroxybutyric acid (3-Hydroxybutyric acid,3 HB), also known as beta-hydroxybutyric acid, is an organic compound. The molecular formula is C 4H8O3, and the molecular weight is 104.11. The substance generally contains three forms, respectively L-form, D-form and DL-form, which have different physical properties and physiological activities. For example, D-3-hydroxybutyrate, which is a normal human metabolite whose level is elevated in elderly patients suffering from depression, is used as a core component of mammalian ketone body metabolism, and is a potential prodrug for treating neurological diseases such as epilepsy, alzheimer's disease, and can improve diabetic pathological conditions by regulating glycolipid metabolism. In the field of ketogenic diets, both the D-form and the L-form are widely studied as energy supplements. In addition, the L-form is deliquescent and forms monoclinic crystals, while the D-form is prone to form syrup-like materials, the preparation of which stable crystals is relatively difficult. At present, a large-scale preparation technology of high-quality and easy-to-operate D-type or L-type single chiral 3-hydroxybutyric acid solid crystals still lacks mature and economic reports. Thus, the current industrial scale process route for preparing high purity, single chiral 3-hydroxybutyric acid (especially D-form) is faced with a significant bottleneck. 3-Hydroxybutyric acid is currently mainly obtained by chemical and fermentation methods. The chemical synthesis method takes petroleum-based derivatives as raw materials, such as the preparation by alkaline hydrolysis of 3-hydroxy ethyl butyrate, although the yield of 95.1% can be realized, the purity or the content is generally lower than 90%, the strict requirements of food-grade, especially medical-grade application on optical purity cannot be met, and the strong acid and alkali used in the reaction process are easy to cause environmental pollution and equipment corrosion. The microbial fermentation rule relies on recombinant strains to convert saccharides into (R) -3-hydroxybutyric acid, for example, the patent application with publication No. CN118813510A constructs an escherichia coli BL21 (DE 3) strain, and fermentation is carried out for 60 hours in a 5L fermentation system to obtain 75.7g/L yield, but the subsequent steps of purification such as ultrafiltration, ion exchange, vacuum distillation and the like are needed, so that the separation cost accounts for more than 60% of the whole production cost, and the mass production economy is poor. In this context, PHB hydrolysis is of increasing interest as an intermediate route connecting biosynthesis and chemical transformations. Poly-3-hydroxybutyrate (PHB) as a microbial intracellular synthesized polyester can be prepared on a large scale by fermenting agricultural wastes, and 3-hydroxybutyrate generated by hydrolysis of the polyester has a single configuration naturally according to the raw materials, but the existing PHB hydrolysis process has multiple technical barriers in industrial application, and the purification process of the hydrolysis product is a key bottleneck for restricting industrialization: (1) The limitations of the traditional hydrolysis process lead to high purification cost, namely the traditional hydrolysis process is neutralized to form a high-salt system after hydrolysis by an acid method, electrodialysis, ion exchange resin and the like are needed to remove salt, adsorption resin, active carbon, inorganic adsorption material and other adsorption products are used for eluting by a solvent for multiple times (such as a patent application with publication number of CN115448829A and the invention name of a preparation method and application of (R) -3-hydroxybutyric acid with high optical purity), and the continuous production is difficult to realize due to the large solvent consumption, low efficiency, high cost and low content (42.13%). (2) The product purity is low, the application is difficult, 3-hydroxybutyric acid is easy to dehydrate and condense to produce dimer, polymer and other oligomers in the production process, and meanwhile, the byproduct crotonic acid (impurity) is accompanied, the existing crystallization process is difficult to realize the high-efficiency separation of the oligomer, crotonic acid and 3-hydroxybutyric acid product, so that the optical purity is low, as in the patent application with publication number CN119822950A, the oligomer residue is remained in the product after resin adsorption, filtration, drying, elution and concentration, the purity is about 95 percent, and the subsequent application is unfavorable. (3) The product is unstabl