Engineering Corynebacterium glutamicum Mutants for 3-Methyl-1-butanol Production

3-Methyl-1-butanol (3MB) is a promising biofuel that can be produced from 2-ketoisocaproate via the common l -leucine biosynthesis pathway. Corynebacterium glutamicum was chosen as a host bacterium because of its strong resistance to isobutanol. In the current study, several strategies were designed to overproduce 3MB in C. glutamicum through a non-fermentation pathway. The engineered C. glutamicum mutant was obtained by silencing the pyruvate dehydrogenase gene complex ( aceE ) and deleting the lactic dehydrogenase gene ( ldh ), followed by mutagenesis with diethyl sulfate (DES) and selection with Fmoc-3-4-thiazolyl- l -alanine (FTA). The mutant could produce 659 mg/L of 3MB after 12 h of incubation. To facilitate carbon flux to 3MB biosynthesis, the engineered recombinant was also constructed without branched-chain acid aminotransferase ( ilvE ) activity by deleting the ilvE gene. This recombinant could produce 697 mg/L of 3MB after 12 h of incubation.