Modification of Enzymes with Smart and Ecofriendly Polymers for High-Performance Cellulose Heterogeneous Catalysis

Abstract

The high-value utilization of cellulose through the enzymatic method is promising for cellulosic ethanol production, but its high cost considerably hinders its industrial application. Immobilization of enzyme to realize its recycling can considerably reduce the cost of the cellulosic biomass conversion. However, effective capture and hydrolysis of the insoluble cellulose via the immobilization system remains considerably challenging. In this study, an advanced enzyme molecule modification method is developed instead of the traditional immobilization method, an ecofriendly and a smart system comprising polyacrylic acid, poly(methacrylic acid), and gelatin was prepared to modify cellulase molecules. Cellulase can be on-demand switched between the mobile state, enabling high reactivity, and the fixed state, facilitating cellulase recovery and reuse. Results showed that the hydrolytic degree of the modified cellulase could be as high as that of free cellulase. In addition, the modified cellulase can be recycled for at least 20 batches, which can largely reduce the catalytic cost. Finally, the system showed excellent biosafety and environment-friendly properties, rendering the catalytic process completely “green”. This feasible and low-cost strategy provides a platform for the cleaner production of cellulosic biofuel.

Keywords: Cellulase modification, Cellulose hydrolysis, Temperature-responsive, Cellulosic ethanol