Bamboo saccharification through cellulose solvent-based biomass pretreatment followed by enzymatic hydrolysis at ultra-low cellulase loadings

The modified cellulose solvent- (concentrated phosphoric acid) and organic solvent- (95% ethanol) based lignocellulose fractionation (COSLIF) was applied to a naturally-dry moso bamboo sample. The biomass dissolution conditions were 50 °C, 1 atm for 60 min. Glucan digestibility was 88.2% at an ultra-low cellulase loading of one filter paper unit per gram of glucan. The overall glucose and xylose yields were 86.0% and 82.6%, respectively. COSLIF efficiently destructed bamboo's fibril structure, resulting in a ∼33-fold increase in cellulose accessibility to cellulase (CAC) from 0.27 to 9.14 m2 per gram of biomass. Cost analysis indicated that a 15-fold decrease in use of costly cellulase would be of importance to decrease overall costs of biomass saccharification when cellulase costs are higher than $0.15 per gallon of cellulosic ethanol.