METHOD FOR ENHANCING THE RATE OF ACID PRODUCTION OF GENETICALLY ENGINEERED BACTERIA PRODUCING L-PHENYLALANINE

摘要

A method for enhancing the rate of acid production of genetically engineered bacteria producing L-phenylalanine is provided, comprising: amplifying the whole phosphoenolpyruvate carboxykinase (pckA) gene by PCR and inserting the amplified PCR product into the original plasmid MDphe-2 producing L-phenylalanine to construct a new plasmid MDphe-3; deleting the global metabolic net regulator csrA gene in the host bacteria of plasmid MDphe-3 by Red system; then transplanting the plasmid MDphe-3 into the host bacteria, in which the global metabolic net regulator csrA gene is deleted, in order to construct new genetically engineered bacteria producing L-phenylalanine; finally validating and reserving the genetically engineered bacteria producing L-phenylalanine with high heredity stability and high production rate of acid. The said method increases the accumulation of PEP which is one of precursors of aromatic amino acids, and at the same time largely converts the carbon metabolic flux into shikimate pathway to ensure that more metabolic flux of aromatic amino acids flows towards the biosynthesis of L-phenylalanine, and further enhances the ability of producing L-phenylalanine by fermenting the genetically engineered bacteria.