Patent ID: 11802300

Abstract:
A genetically engineered strain having high-yield of L-valine is disclosed. Starting from Escherichia coli W3110, an acetolactate synthase gene alsS of Bacillus subtilis is inserted into a genome thereof and overexpressed; a ppGpp 3′-pyrophosphate hydrolase mutant R290E/K292D gene spoTM of Escherichia coli is inserted into the genome and overexpressed; a lactate dehydrogenase gene ldhA, a pyruvate formate lyase I gene pflB, and genes frdA, frdB, frdC, frdD of four subunits of fumaric acid reductase are deleted from the genome; a leucine dehydrogenase gene bcd of Bacillus subtilis replaces a branched chain amino acid transaminase gene ilvE of Escherichia coli; and an acetohydroxy acid isomeroreductase mutant L67E/R68F/K75E gene ilvCM replaces the native acetohydroxy acid isomeroreductase gene ilvC of Escherichia coli. Furthermore, the L-valine fermentation method is improved by using a two-stage dissolved oxygen control. The L-valine titer and the sugar-acid conversion rate are increased.