ABE fermentation from enzymatic hydrolysate of NaOH-pretreated corncobs

Acetone butanol ethanol (ABE) was produced from enzymatic-hydrolyzed corncobs by Clostridium saccharobutylicum DSM 13864. Pretreatment of corncobs was carried out with 0.5 mol L−1 NaOH followed by enzymatic hydrolysis. The yield of total reducing sugars was 917 g kg−1 pretreated (de-lignified) and washed corncobs. The hydrolysate was used without sediments removal for ABE fermentation. A solvent production of 19.44 g L−1 with 12.27 g L−1 butanol was obtained from 55.22 g L−1 sugars, resulting in an ABE yield of 350 g kg−1 and a production rate of 0.54 g L−1 h−1. A control experiment using 55.3 g L−1 mixed sugars resulted in an ABE production of 16.81 g L−1 with 10.26 g L−1 butanol, corresponding to an ABE yield of 300 g kg−1 and a production rate of 0.47 g L−1 h−1, indicating that the enzymatic hydrolysates may contain stimulating compounds that can improve the ABE fermentation.