Immobilized Candida antarctica lipase B (CALB) on functionalized MCM-41: Stability and catalysis of transesterification of soybean oil and phytosterol

Abstract

The mesoporous material MCM-41 was amino-modified with 3-aminopropyltriethoxysilane, and the amino content of modified MCM-41 was 0.16 mmol/g. Then G-MCM-41 was prepared by adding glutaraldehyde. Candida antarctica lipase B (CALB) was immobilized on G-MCM-41 at 45 °C for 5 h to obtain immobilized lipase G-MCM-41-CALB. The lipase protein loading of G-MCM-41-CALB was 87.4 mg/g and its expressed activity was 80.2%. The immobilization efficiency of G-MCM-41-CALB reached 93%. The characterization of G-MCM-41-CALB showed that the mesopores maintained the pore structure, the crystal surface was intact, and the pore size became smaller, indicating that the CALB was immobilized on the carrier. The optimum pH and temperature of G-MCM-41-CALB were 7.0 and 50 °C, respectively. The relative activity of G-MCM-41-CALB was still >50% after 40 days at 4 °C. The thermal stability of G-MCM-41-CALB was improved compared to free CALB. G-MCM-41-CALB was evaluated for its ability to catalyze the transesterification of soybean oil and phytosterol. Results showed a conversion rate of 87.4% and the relative activity of G-MCM-41-CALB was 83% after 7 reuses.