A high-efficiency production of malic acid Aspergillus niger strain, construction method and application

Abstract

The invention relates to a genetically engineered strain of Aspergillus niger that can efficiently produce malic acid. The genetically engineered strain of Aspergillus niger has knocked out the citric acid transporter gene cexA, and overexpressed the glucose transporter gene mstC and hexokinase derived from Aspergillus niger. Genetic engineering strain of Aspergillus niger with gene hxkA, phosphofructokinase gene pfkA and pyruvate kinase gene pkiA. The efficiency of producing malic acid by the genetically engineered strain of Aspergillus niger of the present invention is significantly improved, and the output of fed-batch fermentation in the fermenter on the eighth day reaches 195.72-210g / L, and the conversion rate of malic acid to glucose reaches 1.59-1.64mol / mol, The fermentation cycle was shortened by one day compared with the starting strain, from the original 9 days to 8 days. Excellent strains are provided for the preparation of malic acid by microbial fermentation.

Description

technical field [0001] The invention belongs to the technical field of microorganisms, in particular to an Aspergillus niger strain for efficiently producing malic acid, a construction method and application thereof. Background technique [0002] As an important cell factory, Aspergillus niger has been used in the fermentative production of organic acids for more than 100 years. It is not only a GRAS (generally regarded safe) strain, but also able to utilize cheap carbon sources. L-malic acid, also known as 2-hydroxysuccinic acid, is mainly used in food, medicine and other industries. In the food industry, L-malic acid is mainly used as a food sour agent. Compared with citric acid, it has the characteristics of soft taste, high acidity, and long residence time. It does not damage the oral cavity and teeth, and does not accumulate fat. The safe food sour agent recognized by the international food industry is one of the organic acids with the largest amount and good developme...

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Problems solved by technology

[0003] At present, the production of malic acid by fermentation of Aspergillus niger has problems such as low production efficiency, long fermentation production cycle and high accumulation of by-product citric acid, resulting in high production cost and subsequent complicated malic acid separation and purification process. Therefore, it is necessary to construct an efficient production A strain of Aspergillus niger for malic acid, which is necessary to increase the production efficiency of malic acid, shorten the fermentation cycle and eliminate by-products

[0004] Through the search, no published patent documents related to the patent application of the present invention have been found

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