Mechanisms of bio-additives on boosting enzymatic hydrolysis of lignocellulosic biomass

Abstract

Expensive cellulase is one of the major obstacles hinders large-scale biorefining of lignocellulosic biomass. The cheap and biodegradable additives sophorolipid and whey protein were found to boost enzymatic hydrolysis, their mechanisms were clarified firstly in this study. Results showed that the effects of these additives on enhancing enzymatic hydrolysis were positively correlated with substrate content; when the solid dosage was 20% (w/v), the presence of sophorolipid and whey protein increased glucose yield by 17.8% and 11.9%, respectively; this could be attributed to sophorolipid favor to alleviate the non-productive adsorption between undesired substrates and enzymes caused by hydrophobic and electrostatic forces, and the ability of whey protein to block the site of enzyme adsorption of lignin; high shear and temperature conditions accelerate the inactivation of cellulase, and the addition of sophorolipid and whey protein reduced the inactivation rate by 7.8% and 13.6%, respectively, under enzymatic hydrolysis conditions.