Porous biochar/chitosan composites for high performance cellulase immobilization by glutaraldehyde.

In this work, porous biochar derived from sugarcane bagasse was prepared and then coated with different amounts of chitosan (C@CS) for cellulase immobilization. Cellulase was covalently immobilized on the support by using glutaraldehyde as a linker. The chemical characteristics and morphology of the samples were determined by SEM, BET, FT-IR and XPS. The properties of immobilized enzyme were evaluated by activity recovery, optimum pH value and temperature, and recyclability. The results showed that all the three kinds of immobilized cellulase did not change the optimum pH value of 4 and temperature of 60 °C, and they also exhibited good activity and reusability. Especially for C@CS25 (the feeding ratio of porous biochar to chitosan was 0.5 g: 25 mg), the support retained the morphology of porous biochar well. The corresponding immobilized cellulase kept 67 % activity of free cellulase at pH = 4 and 60 °C, and showed a glucose productivity of 90.8 % even after 10 cycles.