Glycerol supplementation of the growth medium enhances in situ detoxification of furfural by Clostridium beijerinckii during butanol fermentation.
Lignocellulose-derived microbial inhibitors such as furfural and 5-hydroxymethyl furfural adversely affect fermentation of lignocellulosic biomass hydrolysates to fuels and chemicals due to their toxicity on fermenting microbes. To harness the potential of lignocellulose as a cheap source of fermentable sugars, in situ detoxification of furfural and other lignocellulose-derived microbial inhibitors is essential. To enhance in situ detoxification and tolerance of furfural by Clostridium beijerinckii NCIMB 8052 during acetone-butanol-ethanol (ABE) fermentation, the effect of glycerol on NADH/NADPH generation and ABE production by furfural (4, 5, and 6 g/L)-challenged cultures was investigated in this study. In all instances, beneficial outcomes were observed. For example, the fermentation medium supplemented with glycerol and subjected to 5 g/L furfural elicited up to 1.8- and 3-fold increases, respectively, in NADH and NADPH levels in C. beijerinckii 8052 relative to the control culture. These critical changes are the likely underpinnings for the glycerol-mediated 2.3-fold increase in the rate of detoxification of 5 g/L furfural, substrate consumption, and ABE production compared to the unsupplemented medium. Collectively, these results demonstrate that increased intracellular NADH/NADPH in C. beijerinckii 8052 due to glycerol utilization engenders favorable effects on many aspects of cellular metabolism, including enhanced furfural reduction and increased ABE production.
Department of Animal Sciences and Ohio State Agricultural Research and Development Center (OARDC), The Ohio State University, 305 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH, 44691, USA.
Victor
V
Ujor
Chidozie Victor
CV
Agu
Venkat
V
Gopalan
Thaddeus Chukwuemeka
TC
Ezeji
D000096:Acetone / Q000378:metabolism; D001711:Biotransformation; D000440:Butanols / Q000378:metabolism*; D046970:Clostridium beijerinckii / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry*; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005662:Furaldehyde / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism
D000440:Butanols; D003470:Culture Media; D009243:NAD; D000096:Acetone; D000431:Ethanol; D009249:NADP; D005662:Furaldehyde; D005990:Glycerol