Method for improving L-tryptophan fermentation process yield and sugar-acid conversion rate

Abstract

The invention relates to the technical field of amino acid production through a fermentation method, and discloses a method for improving the yield of an L-tryptophan fermentation process and the sugar-acid conversion rate. The method for improving the L-tryptophan fermentation process yield and the sugar-acid conversion rate comprises the following steps: S1, preparing materials; S2, carrying out fermentation culture; s3, seed culture; according to the principle that choline chloride and betaine phosphate have the effects of improving methyl synthesis, enhancing enzyme activity and improving cell permeability on the L-tryptophan producing bacteria, the invention provides a method suitable for improving the L-tryptophan fermentation yield and sugar-acid conversion rate of the tryptophan producing bacteria. By adding a certain amount of choline chloride and betaine phosphate into the culture medium, the purpose of high yield of L-tryptophan is achieved, the whole fermentation period is shortened and the yield and the conversion rate of L-tryptophan are greatly improved under the condition of not increasing additional equipment and human input, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of amino acid production by fermentation, and specifically relates to a method for improving the yield and sugar-acid conversion rate of L-tryptophan fermentation process. Background technique [0002] In recent years, as the research on the application of L-tryptophan in medicine and health care, food processing and feed industry continues to deepen, the market demand for L-tryptophan continues to grow. According to statistics, the domestic tryptophan market in 2020 will The demand is about 50,000 tons, and the annual demand is increasing at a rate of 15%. Therefore, it is of great significance to further optimize the production process of L-tryptophan. [0003] At present, the acid production and conversion rate of L-tryptophan fermentation are still at a low level. One of the reasons is that in the early stage of fermentation, the substrate glucose is used to synthesize L-tryptophan and bacteria, cell gro...

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Problems solved by technology

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for improving the yield of L-tryptophan fermentation process and the conversion rate of sugar and acid, which effectively solves the current problems of L-tryptophan fermentation acid production and The conversion rate is still at a low level, one of the reasons is that the substrate glucose is used to synthesize L-tryptophan and bacteria at the same time in the early stage of fermentation, and there is a carbon source and energy gap between cell growth and L-tryptophan synthesis Competition, too high biomass will inevitably lead to a decrease in sugar-acid conversion rate; the second reason is that in the later stage of fermentation due to the decrease in cell specific growth rate, "fermentation conversion" occurs, and the cells synthesize a large number of by-products such as other amino acids; the third reason is that Insufficient base donors, the synthesis of L-tryptophan is limited, resulting in low acid production and conversion rate; in addition, in the middle and late stages of fermentation, the enzyme activity of the bacteria decreases rapidly, resulting in a decline in the rate of acid production in the later stage

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