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CN-121992045-A - Method for regulating and controlling content ratio of isoleucine to valine in fermentation process and application thereof

CN121992045ACN 121992045 ACN121992045 ACN 121992045ACN-121992045-A

Abstract

The application provides a method for regulating and controlling the content ratio of isoleucine to valine in a fermentation process, which comprises the step of regulating the oxidation-reduction potential of fermentation liquor to-200 to-175 mV when the content of valine in the fermentation liquor is 3.00-5.00 g/L. The application also provides application of the method in producing isoleucine by fermentation, improving the yield and/or purity of the isoleucine and improving the conversion rate of raw materials. According to the application, the oxidation-reduction potential is properly regulated at a specific time, so that the content ratio of isoleucine to valine in the fermentation liquor is obviously increased, and the separation burden of the isoleucine and valine at the downstream is reduced.

Inventors

  • Bai Yingna
  • LIU SHUPENG
  • LIU LEI

Assignees

  • 安徽华恒生物科技股份有限公司
  • 合肥华恒生物工程有限公司

Dates

Publication Date
20260508
Application Date
20241106

Claims (10)

  1. 1. A method of regulating the isoleucine to valine content ratio during fermentation comprising: When the valine content in the fermentation liquor is 3.00-5.00 g/L, the oxidation-reduction potential of the fermentation liquor is regulated to be minus 200 mV to minus 175mV; preferably, the isoleucine is L-isoleucine.
  2. 2. The method of claim 1, wherein the redox potential of the fermentation broth is adjusted to-196 to-175 mV.
  3. 3. The method of claim 1 or 2, wherein the redox potential value of the fermentation broth is adjusted by at least one of adjusting aeration and adjusting agitation speed.
  4. 4. A method according to claim 3, wherein the redox potential of the fermentation broth is regulated by regulating ventilation.
  5. 5. The process according to claim 1 to 4, wherein the ratio of isoleucine to valine in the fermentation broth after the end of the fermentation is 8.00 or more.
  6. 6. The method of any one of claims 1-5, wherein the strain used for fermentation is escherichia coli (ESCHERICHIA COLI), brevibacterium flavum (Brevibacterium flavum), corynebacterium glutamicum (Corynebacterium glutamicum), or Brevibacterium lactofermentum (Brevibacterium lactofermentum).
  7. 7. The method according to claim 6, wherein the strain used for fermentation is E.coli.
  8. 8. The method of claim 7, wherein the E.coli is E.coli with accession number CCTCC NO: M20231916.
  9. 9. The method of any one of claims 1-8, for: a) Fermenting to produce isoleucine; b) Improving isoleucine yield and/or isoleucine purity, and/or C) The conversion rate of raw materials in the production of isoleucine is improved.
  10. 10. The method of claim 9, wherein the feedstock conversion is glucose to isoleucine conversion, and/or threonine to isoleucine conversion.

Description

Method for regulating and controlling content ratio of isoleucine to valine in fermentation process and application thereof Technical Field The application relates to the field of fermentation, and in particular provides a method for regulating and controlling the content ratio of isoleucine to valine in a fermentation process and application thereof. Background L-isoleucine is one of the eight essential amino acids of human body, and has the functions of promoting protein synthesis and muscle growth, reducing blood ammonia level, supplying energy, maintaining blood circulation and immune homeostasis, and the adult needs to be supplemented with at least 20mg/kg (body weight) of L-isoleucine every day. Therefore, in the food industry such as amino acid exercise energy drinks and wheat flour nutrition fortification, the demand for L-isoleucine is very large. In addition, L-isoleucine has an obvious promoting effect on the growth and development of most animals and also has an auxiliary effect on the physiological functions of the milk secretion, nervous system and the like of animals, but because the animals cannot synthesize the L-isoleucine, the L-isoleucine is also very high in demand in the animal feed industry. L-isoleucine is also one of the three major branched-chain amino acids, which plays a critical role in both infant, adolescent and adult growth and development. Meanwhile, the branched chain amino acid has good auxiliary recovery effect on the treatment of diseases such as liver, kidney and the like. Therefore, L-isoleucine is often used together with L-valine and L-leucine as a branched-chain amino acid injection or an oral nutritional liquid for clinical adjuvant therapy, and L-isoleucine at a pharmaceutical level is a high added value amino acid. The L-isoleucine is produced by extraction, chemical synthesis and fermentation. The fermentation method is a method for synthesizing and excessively accumulating L-isoleucine by utilizing the metabolism of microorganisms, has the advantages of low raw material cost, mild reaction condition, easy realization of large-scale production and the like, and is the most main method for producing the L-isoleucine at present. The fermentation method comprises two types of addition precursor fermentation method and direct fermentation method, wherein the addition precursor fermentation method takes glucose as a fermentation carbon source, and specific precursor substances such as alpha-aminobutyric acid, alpha-hydroxybutyric acid, alpha-ketobutyric acid and threonine are added to avoid feedback regulation in the amino acid biosynthesis pathway, so that the precursor fermentation method is effectively converted into L-isoleucine through the action of microorganisms. The direct fermentation method is to select and breed auxotroph and amino acid analogue resistant mutant strain by means of mutagenesis treatment of specific microorganism to relieve feedback inhibition and feedback repression in metabolic regulation, thereby achieving the purpose of excessively accumulating L-isoleucine. At present, most of L-isoleucine-producing bacteria are produced by mutagenesis and breeding of glutamic acid-producing bacteria (e.g., brevibacterium flavum, corynebacterium glutamicum and Brevibacterium lactofermentum). However, with the continuous maturation of fermentation technology and the development of genetic engineering technology and the increase of biochemical information of industrial microorganisms, more excellent L-isoleucine-producing bacteria of genus Bacillus have been developed. At present, a plurality of enterprises produce L-isoleucine through a fermentation method, but the problems of low acid production level of strains, poor extraction technology of fermentation products and the like still exist. Therefore, improving the fermentation and extraction process of L-isoleucine is of great significance in improving the domestic L-isoleucine yield and the product market competitiveness. Analysis of the metabolic pathways of isoleucine and valine shows that the first anabolic pathway of two amino acids branches from pyruvate and isoleucine and valine are synthesized simultaneously by three isoenzymes, resulting in isoleucine fermentation broth often containing more valine impurities which are difficult to separate. Therefore, there is a need to solve the problem of valine co-accumulation with isoleucine during the fermentation process of isoleucine by a fermentation process control strategy. Disclosure of Invention The application provides a method for regulating and controlling the content ratio of isoleucine to valine in a fermentation process, which comprises the following steps: When the valine content in the fermentation liquor is 3.00-5.00 g/L, the oxidation-reduction potential of the fermentation liquor is regulated to be minus 200-minus 175mV. In one or more embodiments of the application, the redox potential of the fermentation broth is adjusted to-196 to-175