Bionic-immobilized recombinant lipase obtained via bio-silicification and its catalytic performance in biodiesel production

Abstract

In this study, bio-silicification was employed to develop a green and simple bionic-immobilization method for the immobilization of recombinant lipase. The results showed that under the optimized bionic-immobilization conditions, a maximum immobilization efficiency and an activity recovery of 97.71% and 89.62%, respectively, were obtained. Further, bionic-immobilization significantly improved the thermal stability, storage stability, and short-chain alcohol resistance of the bionic-immobilized lipase. Furthermore, molecular dynamics simulation of the bionic-immobilization mechanism revealed that the key amino acid residues that facilitated the binding of the recombinant lipase to silica particles included Arg336, Lys345, His391, His392, His394, and His395, indicating that hydrogen bonds had a special effect in intermolecular recognition, and the active center of the bionic-immobilized lipase favored substrate entry due to the conformational changes of Phe291 and Ile320. Finally, biodiesel was prepared using the bionic-immobilized lipase as catalyst, and after optimizing the enzymatic process, the biodiesel yield reached 91.04% using 20% immobilized lipase dosage within 12 h at 45 °C, and a catalytic activity of 55.02% was observed following the reutilization of the bionic-immobilized lipase seven times. These findings suggest that bionic-immobilization is a novel and rapid method to realize recombinant enzyme immobilization, and can provide economic and ecological support for the biocatalytic preparation of industrial products.