In Situ Saccharification of Cellulose using a Cellulase Mixture and Supplemental β-glucosidase in Aqueous-Ionic Liquid Media

In situ enzymatic saccharification is one promising approach to efficiently convert non-food biomass to glucose as a platform chemical. The goal of the present research was to illustrate the catalytic behaviors and deactivation mechanisms of cellulase and cellobiase in an aqueous-ionic liquid (IL) media. The hydrolysis reaction rate was considerably increased because of the increased porosity and reduced crystallinity of the substrate. To lower the inhibitory effect of accumulated cellobiose on cellulase, a multi-enzyme synergetic system was explored. Compared with the single cellulase saccharification, addition of cellobiase resulted in a substantial increase in total reducing sugars (TRS) yield (88.0% vs. 59.1%) and glucose yield (40.6% vs. 28.9%) when the activity unit ratio of cellobiase/cellulase was 0.95. Cellulase showed a higher stability in aqueous 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac) media. However, the activity of cellobiase quickly decreased, by 66.5%, after 6 h of incubation.