Saccharomyces cerevisiae gene engineering bacteria for producing succinic acid and application thereof

Abstract

The invention discloses saccharomyces cerevisiae gene engineering bacteria for producing succinic acid and application thereof, and belongs to the fields of genetic engineering and fermentation engineering. Malate dehydrogenase gene RoMDH from rhizopus oryzae is adopted to replace PDC1, the yield of ethanol obtained by fermentation of wild saccharomyces cerevisiae reaches the maximum value 13.55 plus or minus 1.062g / L, and the yield of improved strain MP ethanol is 11.09 plus or minus 0.539g / L, and compared with the yield obtained by adopting the wild type, the yield is reduced by 18.15 percent. On the basis, SDH2 gene is knocked out. After culture medium optimization, MP Delta S deleted strain can accumulate succinic acid by 0.698 plus or minus 0.0285g / L, and by contrast, the wild saccharomyces cerevisiae does not accumulate succinic acid. The saccharomyces cerevisiae gene engineering bacteria can effectively reduce the loss of a carbon flow, creates a condition for the engineering yeast to efficiently produce succinic acid, and has a good industrial application value and prospect.

Description

technical field [0001] The invention relates to a succinic acid-producing Saccharomyces cerevisiae genetically engineered bacterium and an application thereof, belonging to the fields of genetic engineering and fermentation engineering. Background technique [0002] Succinic acid is a four-carbon dibasic acid with the scientific name butanedioic acid. Succinic acid has more than 30 important derivative chemicals: tetrahydrofuran, 1,4-butanediol, γ-butyrolactone, maleic acid and fumaric acid, etc., with huge market space. The main sour agent and flavoring agent in the food industry, can be used in the synthesis of sedatives, pH regulators, contraceptives, anticancer drugs, etc. , Foaming agent and lubricant etc. It is worth mentioning that, as the main raw material of biodegradable plastic polybutylene succinate (completely degradable), succinic acid has broad application prospects. In view of the above-mentioned important application value and many advantages of succinic ...

AI Technical Summary

Problems solved by technology

However, the use of Saccharomyces cerevisiae to ferment and produce succinic acid faces the following problems: (1) Batch fermentation produces a large amount of ethanol under conditions of high concentration of sugar and ventilation. (2) Succinic acid is an intermediate metabolite in the TCA cycle. Saccharomyces cerevisiae itself does not have a metabolic pathway for excessive accumulation of succinic acid. It is necessary to construct a synthetic pathway for succinic acid, but succinic acid has a relatively high reducing potential. The TCA reduction pathway accumulates succinic acid, which requires two reducing hydrogens, which is relatively difficult to accumulate; (3) to achieve the reduction of ethanol production, after pyruvate is accumulated, how to further convert pyruvate into the target product succinate needs to strengthen the carboxylation reaction of pyruvate , so that it can be converted into oxaloacetate, enter the TCA cycle, and then be converted into succinic acid. This strategy is the key to improving the production of succinic acid

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