Reusing the Acetone-Butanol-Ethanol Separated Broth as the Lignocellulose Pretreatment Liquor for Fresh Corn Stalk Biorefinery

Abstract

Biorefinery of fresh corn stalk was conducted to produce bio-butanol via acetone-butanol-ethanol (ABE) fermentation. After the first-stage juice fermentation and the following ex situ product recovery, the consolidate process was further intensified by recycle the organic acids containing butanol fermentation wastewater (BFW) as the pulping liquor for the fractionation of the corn stalk bagasse (CSB), afford to a second-stage cellulosic ABE production. The effect of pulping temperature and solid loading on fermentable sugars production were investigated. 32.45±0.85 g/L of total monomer sugars and 82.73±2.21% of yield can be achieved at 180 °C with 10% (w/v) biomass loading. Correspondingly, ABE concentration and productivity of 10.94±0.65 g/L and 0.18±0.01 g/L·h were obtained after semi-simultaneous saccharification and fermentation (S-SSF) of the corn stalk pulps. Overall, total 54.07±1.25 g (ABE) can be produced from 1 kg of fresh corn stalk by adopting the ABE-separated BFW pulping strategy.

Keywords: Fresh corn stalk, Acetone-butanol-ethanol fermentation, Ex situ product recovery, Acid pretreatment, biorefinery