Genetically engineered strain with high yield of L-valine and method for producing L-valine by fermentation

A genetically engineered strain for producing L-valine, comprising:

• E. coli W3110 as taken as a starting strain;
• a gene alsS encoding acetolactate synthase of Bacillus subtilis is inserted into a genome of the E. coli W3110 and subjected to overexpression;
• a mutant gene spoTM is inserted into the genome of the E. coli W3110 and subjected to overexpression, wherein the mutant gene spoTM encodes a mutant R290E/K292D of the wild-type E. coli ppGpp 3′-pyrophosphate hydrolase as shown in SEQ ID NO:
• 63;
• a gene ldhA encoding lactate dehydrogenase, a gene pflB encoding pyruvate formate lyase I, and genes frdA, frdB, frdC and frdD for four subunits of fumarate reductase are deleted from the genome of the E. coli W3110;
• a gene bcd encoding leucine dehydrogenase of Bacillus subtilis replaces a gene ilvE encoding branched-chain amino acid transaminase of the E. coli W3110;
• and
• a mutant gene ilvCM replaces a gene ilvC encoding acetohydroxy acid isomeroreductase of the E. coli W3110, wherein the mutant gene ilvCM encodes a mutant L67E/R68F/K75E of the wild-type E. coli acetohydroxy acid isomeroreductase as shown in SEQ ID NO:
• 65.