Method for purifying polymalic acid in biological fermentation broth

Abstract

The invention discloses a method for purifying polymalic acid in biological fermentation broth, which includes: preparation of polymalic acid fermentation broth; removal of insoluble matters (such as thalli) in fermentation broth; primary decoloration; ultrafiltration of macromolecular polysaccharide; nanofiltration of micromolecular impurities; secondary decoloration; and freeze-drying. The method of plate-frame filtration, ultrafiltration, nanofiltration, enzymolysis and decoloration is adopted to extract and purify polymalic acid in biological fermentation broth. A multi-stage membrane separation technique is used, organic solvents are not added in the whole process, the physical method is mainly utilized to remove impurities in the fermentation broth, and thereby polymalic acid with high content and purity is obtained.

Description

technical field [0001] The invention belongs to the technical field of biosynthesis and purification, in particular to a method for purifying polymalic acid in biological fermentation liquid. Background technique [0002] Polymalic acid [poly(β-)malic acid, hereinafter referred to as PMLA] is a polymer polyester compound with malic acid as the only monomer. PMLA and its derivatives are a new class of biopolymer materials with a special three-dimensional structure and ester groups on the main chain, which can be degraded spontaneously or enzymatically under water environment conditions. Its monomer malic acid widely exists in various organisms and participates in the TCA cycle metabolism pathway of organisms. [0003] The side chain of PMLA contains several highly hydrophilic carboxyl groups, so the main properties of PMLA are reflected in its high water solubility, water absorption, absorbability, biocompatibility, degradability, and chemical derivatization. Non-toxic, non...

AI Technical Summary

Problems solved by technology

There are many methods of chemical synthesis, but the cost of chemical synthesis is high, the operating conditions are harsh, and the pollution is heavy. The molecular weight of the obtained polymer is lower than that of the polymer obtained by biological fermentation. The molecular weight of chemical synthesis can only reach 174kDa at most, while The method can reach up to 200-760kDa, and the PMLA produced by the fermentation method is all β-type

[0005] At present, the bottlenecks faced by domestic PMLA production mainly include the following aspects: 1. During the fermentation process, Aureobasidium pullulans will produce substances such as black and yellow-green pigments, which make it difficult to remove the pigments; Pullulan polysaccharide makes it difficult to separate sugar from PMLA; 3. In the traditional process, organic solvent alcohol precipitation or ion exchange resin is used to extract PMLA, which will lead to an increase in production costs and potential safety hazards during industrialized mass production

[0006] Although it has been possible to provide gram-level sodium salt, calcium salt, potassium salt or free acid of PMLA from the biotechnology approach, due to the long fermentation cycle of PMLA, the extraction process is mostly based on organic solvent precipitation, which is harmful to the environment and expensive. Affected by high-level factors, the mass production of PMLA is still greatly restricted.

There are many articles and patents related to PMLA related to the application and fermentation of PMLA, but relatively few about the extraction method

Moreover, these relevant researches and reports in our country are only at the laboratory level, and no one has actually carried out industrial production.