Mesoporous silica nanoparticles for β-glucosidase immobilization by templating with a green material: Tannic acid

Bioconversion of lignocellulosic biomass to biofuels through enzymatic hydrolysis has become a promising strategy to reduce our dependence on fossil fuels. beta-Glucosidase (BG) is a key enzyme in the enzymatic degradation of cellulose. However, free beta-glucosidase is relatively unstable, costly and difficult to recover. Immobilization of beta-glucosidase may help to improve its reusability and stability, allowing developing a sustainable low-carbon and resource-efficient circular economy. BG was immobilized by adsorption on synthesised tannic acid templated mesoporous silica nanoparticles (TA-MSNPs). The synthesis procedure adopts a green templating agent cheap and biocompatible. Textural and morphological characterization was performed. We studied the effect induced by the morphology, pore size and surface features of supports, by using different amounts of templating agent, on the catalytic performance of the biocatalyst. The immobilization procedure used preserved most of the secondary structure of the enzyme and consequently its catalytic activity. The biocatalyst exhibiting the best activity and operational stability is obtained with the sorbent prepared with the largest quantity of tannic acid. In this case, the mesopores are too small for the enzyme to enter them, and the large amount of adsorbed enzyme is due to its peculiar surface features, favouring the formation of a multilayer enzyme corona.