Effects of and Medium Modifications on Acetone-Butanol-Ethanol Production From Switchgrass.

The presence of lignocellulose-derived microbial inhibitory compounds (LDMICs) in lignocellulosic biomass (LB) hydrolysates is a barrier to efficient conversion of LB hydrolysates to fuels and chemicals by fermenting microorganisms. Results from this study provide convincing evidence regarding the effectiveness of metabolically engineered NCIMB 8052 for the fermentation of LB-derived hydrolysates to acetone-butanol-ethanol (ABE). The engineered microbial strain (_SDR) was produced by the integration of an additional copy of a short-chain dehydrogenase/reductase (SDR) gene (3904) into the chromosome of NCIMB 8052 wildtype, where it is controlled by the constitutive thiolase promoter.

Viable strategies for enhancing acetone-butanol-ethanol production from non-detoxified switchgrass hydrolysates.

A process engineering strategy was investigated towards developing a viable scheme for effective conversion of hydrothermolysis pretreated non-detoxified switchgrass hydrolysates (SH) to acetone butanol ethanol (ABE) using a metabolically engineered strain of Clostridium beijerinckii NCIMB 8052, C. beijerinckii_AKR. The engineered strain was modified by homologous integration into the chromosome and constitutive expression of Cbei_3974, which encodes an aldo-keto reductase.