Genetically engineered bacterium of Bacillus licheniformis with high yield of phenyllactic acid, method for producing phenyllactic acid and application

Abstract

The invention relates to a genetically engineered bacterium of Bacillus licheniformis with high yield of phenyllactic acid. A construction method of the genetically engineered bacterium is as follows:modifying bacillus licheniformis TCCC 11148 (2709) or/Escherichia coli Rosetta (DE3) by a genetic engineering and metabolic engineering technology. The construction method comprises three steps of molecular manipulations: inhibiting branching of chorismic acid to a tryptophan pathway; inhibiting branching of prephenic acid to a tyrosine pathway; and over-expressing phenyllactic acid synthase/aminotransferase. By modifying a Bacillus licheniformis aromatic amino acid metabolic pathway, knocking out a phenyllactic acid synthesis precursor phenylalanine synthesis pathway competitive enzyme geneand overexpressing a most direct precursor enzyme (lactic dehydrogenase) gene for phenyllactic acid synthesis, the yield of phenyllactic acid is greatly increased, and a new thought is provided for obtaining a target product phenyllactic acid. Finally, the yield of the obtained phenyllactic acid production strain reaches to 17.8 g/L after fermentation, and the strain has certain potential in industrial production of phenyllactic acid.

Description

technical field [0001] The invention belongs to the field of genetic technology, in particular to a genetic engineering bacterium of high-yielding bacillus licheniformis, a method for producing phenyllactic acid and an application thereof. Background technique [0002] Phenyllactic acid (PLA), also known as 2-hydroxy-3-phenylpropionic acid, has the molecular formula C 9 h 10 o 3 . In the natural environment, phenyllactic acid is mostly produced in honey and cheese, and it is a light yellow powder after preparation, which is a small molecular substance with excellent solubility. In the prior art, the synthesis of phenyllactic acid is mainly a chemical synthesis method and a biosynthesis method, and the biosynthesis can be obtained through the metabolism of various microorganisms, the most important of which is produced by fermentation of lactic acid bacteria. Phenyllactic acid is widely used in food and drug preservatives because of its broad antibacterial spectrum, high ...

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Problems solved by technology

However, Escherichia coli has a certain biological safety problem. The value of Escherichia coli is one of the important indicators for daily drinking water and food safety detection. Therefore, once the operation error in the early cultivation pollutes the environment, it may cause huge industrial losses.

[0007] Secondly, most of the whole-cell catalysis methods need to add precursor substances to catalyze the formation of the target product, while the precursor substances of phenyllactic acid, phenylalanine and phenylpyruvate, are sold at a high price, and the profit value is relatively low compared with the price of the target product, so it is not suitable industrial mass production

[0008] Through the search, no patent publications related to the patent application of the present invention have been found

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