A kind of method of fermentative production L-isoleucine

Abstract

The invention provides a method for producing L-isoleucine by fermentation, and relates to the technical field of amino acid production. The method uses Corynebacterium crenatum as an L-isoleucine producing bacterium, and includes the steps of activating culture, seed culture, fermentation culture and extraction of L-isoleucine. Adding asparagine to a fermentation medium significantly increases the conversion rate of sugar acid and the yield of L-isoleucine; by controlling the ratio of glucose to ammonium sulfate in the fermentation medium, the content of ammonium nitrogen in a fermentation broth is significantly reduced; and in addition, the extraction process of L-isoleucine in the fermentation broth is optimized to improve the purity of L-isoleucine and avoid generation of a large amount of wastewater. The method is simple and easy to control and low in cost and has high industrial practical value.

Description

technical field [0001] The invention relates to the technical field of amino acid production, in particular to a method for producing L-isoleucine by fermentation. Background technique [0002] L-Isoleucine (L-Isoleucine) is one of the eight essential amino acids for the human body. It is the same branched-chain amino acid as L-leucine and L-valine. It was first isolated from sugar beet syrup in 1904. L-isoleucine is a raw material for the synthesis of human hormones and enzymes. It has the effect of promoting protein synthesis and inhibiting its decomposition, and plays an important role in human life activities. It has been widely used in biomedicine, food industry, cosmetics, electrochemistry, tissue engineering, photochemistry and other fields. [0003] At present, there are three types of L-isoleucine production methods: extraction method, chemical synthesis method and fermentation method. Due to the difficulty in separating the L-isoleucine produced by the extraction ...

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Problems solved by technology

Chinese patent publication CN108796003A discloses a method for improving the production of L-isoleucine, which increases fatty acid and / or hemin in the fermentation medium to produce L-isoleucine with Corynebacterium bacillus. The yield has increased from 15g / L to 19.2g / L, but the yield of L-isoleucine is still low

Chinese patent announcement CN103409476B discloses a method for fermentation and separation and purification of L-isoleucine. In this method, Brevibacterium lactose fermentum is subjected to mutagenesis breeding and resistance screening. After optimizing the fermentation medium, chitosan pretreatment and L-isoleucine is obtained after separation and purification methods such as ultrafiltration, and its acid production rate is below 32.7g / L, and its purity does not exceed 99.2%. This method is complicated to operate, and its purity and acid production rate still need to be improved

In addition, during the fermentation process of L-isoleucine, it is necessary to add ammonia water to adjust the pH and supplement the nitrogen source. However, because the ammonia water in the middle and late stages of fermentation only plays a role in adjusting the pH, it has not been used in time, resulting in Ammonium nitrogen content is high, causing great environmental pollution

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