Hybrid Cellulase Aggregate with a Silica Core for Hydrolysis of Cellulose and Biomass

Cellulase is an important enzyme for hydrolyzing cellulose to form glucose. To recycle cellulase after the reaction, cellulase is often immobilized on solid supports but its activity is also compromised. In this study, we show a new hybrid cellulase aggregate with a silica core, which is prepared by physical adsorption of cross-linked cellulase on a highly porous solid support silica gel. The hybrid cellulase aggregate exhibits highest activity at pH 4.8 and 51°C, similar to the optimum condition of free cellulase. This hybrid cellulase aggregate can produce 3.4 g/L of glucose within 2 h, which is two times higher than glucose produced by using cross-linked cellulase aggregate alone (without silica core). Another advantage of the hybrid cellulase aggregate is that it can settle down naturally after the hydrolysis of cellulose, thanks to the presence of the silica core. To show its practical applications, we also study the hydrolysis of palm oil fiber by using the hybrid cellulase aggregate. Up to 5.0 g/L of glucose can be produced within 24h, and this process can be repeated five times with only 19% decrease in activity.