Genetic engineering bacterium for producing L-leucine, and application of genetic engineering bacterium

The invention relates to a genetic engineering bacterium for producing L-leucine, and application of the genetic engineering bacterium, and belongs to the field of metabolic engineering. The genetic engineering bacterium is obtained by an isopropylmalate synthetase encoding gene leuA[M] capable of relieving L-leucine feedback inhibition through overexpression in a host cell, an acetolactate synthase encoding gene ilvBN[M] capable of relieving L-leucine feedback inhibition, a 3-isopropylmalate dehydrogenase encoding gene leuB and a 3-isopropylmalate dehydratase encoding gene leuCD. Acetohydroxyacid synthase encoded by the leuA[M] relieves the feedback inhibition function of the L-leucine for the acetohydroxyacid synthase, in addition, the activity of the acetohydroxyacid synthase is not obviously lowered than wild leuA encoded isopropylmalate synthetase. The L-leucine genetic engineering bacterium does not have nutritional deficiencies, is quick in growth, and has a short fermentation period, a high yield and