Economic optimization of in situ extraction of inhibitors in acetone-ethanol-butanol (ABE) fermentation from lignocellulose

Production of butanol from lignocellulosic biomass: recent advances, challenges, and prospects

Due to energy and environmental concerns, biobutanol is gaining increasing attention as an alternative renewable fuel owing to its desirable fuel properties. Biobutanol production from lignocellulosic biomass through acetone-butanol-ethanol (ABE) fermentation has gained much interest globally due to its sustainable supply and non-competitiveness with food, but large-scale fermentative production suffers from low product titres and poor selectivity. This review presents recent developments in lignocellulosic butanol production, including pretreatment and hydrolysis of hemicellulose and cellulose during ABE fermentation. Challenges are discussed, including low concentrations of fermentation sugars, inhibitors, detoxification, and carbon catabolite repression. Some key process improvements are also summarised to guide further research and development towards more profitable and commercially viable butanol fermentation.

Feasibility of using biochar as buffer and mineral nutrients replacement for acetone-butanol-ethanol production from non-detoxified switchgrass hydrolysate

Biochar can be an inexpensive pH buffer and source of mineral and trace metal nutrients in acetone-butanol-ethanol (ABE) fermentation. This study evaluated the feasibility of replacing expensive 4-morpholineethanesulfonic acid (MES) P2 buffer and mineral nutrients with biochar made from switchgrass (SGBC), forage sorghum (FSBC), redcedar (RCBC) and poultry litter (PLBC) for ABE fermentation. Fermentations using Clostridium beijerinckii ATCC 51743 in glucose and non-detoxified switchgrass hydrolysate media were performed at 35 °C in 250 mL bottles for 72 h. Medium containing buffer and minerals without biochar was the control. Similar ABE production (about 18.0 g/L) in glucose media with SGBC, FSBC and RCBC and control was measured. However in non-detoxified switchgrass hydrolysate medium, SGBC, RCBC and PLBC produced more ABE (about 18.5 g/L) than the control (10.1 g/L). This demonstrates that biochar is an effective buffer and mineral supplement for ABE production from lignocellulosic biomass without costly detoxification process.