Acetone-butanol-ethanol production by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) methods using acorns and wood chips of Quercus acutissima as a carbon source

We investigated the production of acetone-butanol-ethanol (ABE) from acorns (starchy material) and wood chips (cellulosic material) of Quercus acutissima through separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) by Clostridium acetobutylicum NBRC13948. With acorns, 15.45 g/L of ABE was obtained in 96 h of fermentation time from the enzymatic hydrolyzate of acorns by SHF. From the SSF, it was found that ABE (16.70 g/L, 120 h) was produced without enzyme addition, given that C. acetobutylicum NBRC 13948 possesses an amylolytic enzyme. With wood chips, steam explosion was used for pretreatment. In the SHF, when the enzymatic hydrolyzate of residue of water and methanol extraction after pretreatment was used as the substrate, the maximum ABE concentration, 15.29 g/L, was obtained in 120 h. From the SSF, 13.41 g/L of ABE was obtained in 144 h, and it was determined that sufficient enzyme loading was 7.8 mg of protein to 1 g of dry substrate.