Supramolecular biosourced hydrogelator: a green tool for tailoring the pore size of mesostructured silica for enzyme immobilization

Abstract

Herein, we reported the design of a supported biocatalyst through the physisorption of Mucor miehei lipase (Mm-L) onto SBA-15, followed by the addition of a supramolecular biosourced hydrogelator to reduce the mesopore diameter and prevent enzyme leaching. Prior to enzyme immobilization, the effect of the hydrogel on the structural and textural characteristics of the mesostructure was investigated. Results showed that the presence of the hydrogel did not affect mesopore ordering but successfully reduced the mesopore diameter as targeted. Subsequently, as a potential application of mesopore size control by the hydrogel, the supported biocatalyst was prepared and tested for the synthesis of biodiesel through the transesterification of rapeseed oil with methanol. The reaction was performed under previously optimized conditions. Reusability tests of the supported biocatalysts showed that, in the presence of the hydrogel, the biocatalyst exhibited higher operational stability, remaining effective for up to 5 consecutive runs, than the corresponding physisorbed enzyme without the hydrogel, which was efficient for only 2 consecutive runs. This clearly demonstrated that the addition of the hydrogel limited enzyme leaching.