Cellulase

Fungal cellulases typically have low β-glucosidase (BG) content, which precludes efficient cellulose hydrolysis. Researchers describe here an easy co-immobilization procedure of BG and cellulase by adsorption on wrinkled mesoporous silica nanoparticles having radial and hierarchical open pore architectures with smaller (WSN) and larger (WSN-p) inter-wrinkle distances. Immobilizations were performed separately (WSN for BG and WSN-p for cellulase), simultaneously (on the same vector, WSN-p), and sequentially (on the same vector, WSN-p) to try to optimize cellulase and BG synergy. Results indicated that the biocatalyst prepared by simultaneous immobilization of BG and cellulase on the same vector (WSN-p) gave the best results. In this case, adsorption resulted in a 20% immobilization yield, corresponding to an enzyme loading of 100 mg/g of support. A yield of reaction of 82% and 72 μmol/min·g of activity were reached, which were evaluated during the hydrolysis of cellulose extracted from Eriobotrya japonica leaves. Conditions for all reactions were 50°C. After 9 cycles of reuse, the biocatalyst retained 83% of its initial yield of reaction. Furthermore, it showed better stability than a free enzyme mixture over a broad range of temperatures, retaining 72% of its initial yield of reaction even at 90°C.

Fig. 2 Co-immobilization of cellulase and β-glucosidase into mesoporous silica nanoparticles for the hydrolysis of cellulose. (Pota G, et al. 2022)