Butanol production from corncob residue using Clostridium beijerinckii NCIMB 8052

Aims: To determine whether corncob residue (CCR) could be a good substrate for butanol production. Methods and Results: In this study, Ca(OH)2 detoxification technique was used to remove inhibitors of lignocellulose enzymatic hydrolysis. During fermentation of untreated corncob residue hydrolysate (CCRH) by Clostridium beijerinckii NCIMB 8052, cell growth was inhibited and only 3.8 g l-1 acetone, butanol and ethanol (ABE) was produced. After pretreatment with Ca(OH)2, enzymatic hydrolysis of CCR resulted in 49.3 g l-1 total sugars, about twofold of that of untreated one. In the fermentation of the Ca(OH)2-detoxified CCRH, sugar utilization ratio was increased by 27.3%. When using the Ca(OH)2-detoxified CCRH supplemented with 10 g l-1 glucose, 16.0 g l-1 ABE was produced, resulting in an ABE yield of 0.32 and a productivity of 0.33 g l-1 h-1. Conclusion: The results in this study suggest that CCR was a good carbon source for ABE fermentation. Significance and Impact of the Study: It is the first time to use CCR as substrate for butanol production. Ca(OH)2 detoxification pretreatment was proved to be an effective method to improve enzymatic digestibility of lignocellulose.