Enhanced methanol tolerance of ZIF-8-immobilized Aspergillus oryzae lipase for biodiesel production from used cooking oil
Shuaibo Xia, Cai Shen, Jiale Lin, Maolin Tu, Chin Ping Tan, Ling‐Zhi Cheong
Abstract
The absorption process of Aspergillus oryzae lipase (AOL) onto the surface of ZIF-8 was elucidated using molecular dynamic (MD) simulation. AOL are absorbed onto the surface of ZIF-8 via hydrogen bonding, electrostatic and van der Waals interaction with minimal changes to its native configurations. Unlike free AOL, AOL@ZIF-8 can maintain its structure in simulated methanol solutions. To verify the results from MD simulation, AOL was immobilized onto ZIF-8 (AOL@ZIF-8: immobilization efficiency of 64.71 % and a protein loading of 57.36 mg/g) and characterized using SEM, FTIR, and XRD. As compared to free AOL, AOL@ZIF-8 demonstrated higher transesterification activity with an activity recovery of 106.18 %. In agreement with MD simulations, AOL@ZIF-8 exhibited enhanced stability in wide range of pH and under presence of alcohol solution. AOL@ZIF-8 can be used to catalyze transesterification of used cooking oil for production of biodiesel (FAME content of 81.19 %).