Protective effects of five surfactants on cellulase in the saccharification of corn stover based on the impeded Michaelis-Menten model

Abstract

Protective effects of five surfactants were investigated relative to the saccharification of lignocellulose using the impeded Michaelis-Menten model (IMM). The yield of total reducing sugar (Ytrs) and cellulase activity were indexed as the effect of surfactant. The IMM was used to fit the correlation between Ytrs and reaction time to obtain the index (Kobs,0) reflecting the accessibility between cellulose and lignocellulose and the comprehensive index (Ki) reflecting cellulase inactivation and non-specific site adsorption. Results showed that the strongest protective effect was found from polyoxyethylene (80) sorbitan monooleate, followed by rhamnolipid. The surfactants protected cellulase from inactivation and nonspecific site adsorption of lignocellulose in the saccharification, leading to enhanced cellulase activity, especially with respect to carboxymethyl cellulase (CMCase) and filter paper enzyme (FPase) activities. The maximum Ytrs was obtained when the CMCase activity was 136.2 U/mL, while the FPase and β-glucosidase activities should be as high and low as possible, respectively, under the optimized condition. These findings lay the foundation for improving the saccharification efficiency of cellulase and reducing the cost of saccharification of biomass cellulose.