Production of high levels of 2,3-butanediol from renewable crude glycerol by Klebsiella pneumoniae GEM167 using metabolic engineering and control of oxygen transfer efficiency

Abstract

Numerous industries use 2,3-butanediol as a bulk chemical. This study aimed to develop a technique for the commercial production of 2,3-butanediol from glycerol using K. pneumoniae GEM167 strain with enhanced oxidative pathways. We developed K. pneumoniae GEM167 Delta adhE Delta ldhA , a strain that has decreased production of competitive metabolites (ethanol and lactate) and increased production of 2,3-butanediol. We investigated the correlation between the oxygen transfer coefficient and 2,3-butanediol production by modifying the agitation speed and aeration rate. K. pneumoniae GEM167 Delta adhE Delta ldhA provided a high titer (102.9 +/- 3.1 g/L) and productivity (2.14 +/- 0.06 g/L/h) of 2,3-butanediol with no detectable 1,3-propaendiol production under specific culture conditions (37 degrees C, 700 rpm, 2.0 vvm, and pH 6.0). To the best of our knowledge, the productivity of 2,3butanediol from glycerol in this study is the highest yet reported. And the substitution with crude glycerol enhanced the titer (105.3 +/- 2.8 g/L) and productivity (2.19 +/- 0.06 g/L/h) of 2,3-butanediol.