Cloning of the genes concerned in phenylalanine biosynthesis in Corynebacterium glutamicum and its application to breeding of a phenylalanine producing strain.

Abstract

The chorismate mutase and prephenate dehydratase genes of phenylalanine producing Corynebacterium glutamicum K38, which is resistant to p-fiuorophenylalanine and m-fluorophenylalanine, were cloned into plasmid pCE53 in C. glutamicum KY9456, which lacks chorismate mutase and prephenate dehydratase. One of the resultant plasmids, pCmB4, contained a 9.4kb Bam HI DNA fragment inserted into the unique BamHI site of pCE53. Plasmid pCmB4 complemented a phenylalanine and tyrosine double auxotroph of C. glutamicum KY9456. Introduction of pCmB4 into C. glutamicum RRL5 resulted in an about ten times increase in chorismate mutase activity. C. glutamicum K38 carrying the plasmid accumulated 19.0mg/ml of phenylalanine (50% increase over the yield of K38).