Production of 2,3-butanediol from acid hydrolysates of Jatropha hulls with Klebsiella oxytoca

► Neutral detergent removed the extractives of Jatropha hulls to avoid inhibitors. ► A two-step process hydrolyzed Jatropha hulls with hydrolysis yield 64%. ► Yields of diol were 35.6% and 41.4% in flasks from the two-step hydrolysates. ► Fermentation time was reduced from 60 in flasks to 40 h in a controlled bioreactor. ► Glucose from the second-step hydrolysis was more suitable for fermentation.