Preparation of carrierized cellulase Cellulase@MIL-88B(Fe) and its enzymatic properties

Abstract

In this study, cellulase was modified by immobilization technique using MIL-88B(Fe) as the carrier, and the immobilization temperature, time, cellulase concentration and pH of 30°C, 6 h, 1.2 mg/mL and 5.0, respectively, were investigated as the optimal preparation conditions. Characterization analysis using FT-IR, XRD and TGA revealed that the successful immobilization of cellulase on MIL-88B(Fe) did not disrupt the integrity of the carrier lattice structure. Compared with the free enzyme, Cellulase@MIL-88B(Fe) maintained 78% and 85.21% of its activity after 10 cycles and 49 d, respectively, and its t1/2 and Ed values were higher than those of the free enzyme, and it was able to maintain a higher activity over a wider pH and temperature range, indicating its higher thermal stability and heat-loss activity. In addition, the Km of Cellulase@MIL-88B(Fe) (1.46 mg/mL) was slightly higher than that of free cellulase (1.41 mg/mL), and Cellulase@MIL-88B(Fe) was able to be applied in the actual enzymatic digestion of corn cobs.