Process for producing l-threonine

Abstract

The process for producing L-threonine consists in that there is cultivated a producer of L-threonine in the capacity of which is used the Escherichia coli strain VNIIgenetika M-1 deposited in the Central museum of commercial microorganisms under the All-Union Research Institute for Genetics and Selection of Commercial Microorganisms at a registration No. IIMIIB-1856. The above strain has been selected on the basis of natural variability of the Escherichia coli strain VNIIgenetika VL 334/p YN7), obtained by virtue of the genetic engineering techniques through increasing the dose of mutant genes capable of a higher rate of L-threonine production, by introducing a multicopy hydrid plasmid carrying said genes, into a mutant recipient strain. The abovesaid producer is cultivated on a nutrient medium, containing sources of carbon, nitrogen, and some mineral salts in the presence of an antibiotic penicillin, the resultant biomass being then separated from the culture fluid, whereupon the end product is isolated.