Metabolic engineering of Paenibacillus polymyxa for effective production of 2,3-butanediol from poplar hydrolysate.

2,3-Butanediol is an essential renewable fuel. The synthesis of 2,3-butanediol using Paenibacillus polymyxa has attracted increasing attention. In this study, the glucose-derived 2,3-butanediol pathway and its related genes were identified in P. polymyxa using combined transcriptome and metabolome analyses. The functions of two distinct genes ldh1 and ldh3 encoding lactate dehydrogenase, the gene bdh encoding butanediol dehydrogenase, and the spore-forming genes spo0A and spoIIE were studied and directly knocked out or overexpressed in the genome sequence to improve the production of 2,3-butanediol. A raw hydrolysate of poplar wood containing 27 g/L glucose and 15 g/L xylose was used to produce 2,3-butanediol with a maximum yield of 0.465 g/g and 93 % of the maximum theoretical value, and the total production of 2,3-butanediol and ethanol reached 21.7 g/L. This study provides a new scheme for engineered P. polymyxa to produce renewable fuels using raw poplar wood hydrolysates.