Microbial Cellulases Immobilized in/on Porous Supports

Abstract

Biodegradation of cellulose by enzymatic hydrolysis using cellulases has an important value in biotechnology and the immobilization of enzyme on inorganic materials is very useful in practical applications. Enzymatic preparations with cellulase and cellobiase activities from Trichoderma viride were liophylized from the culture medium and immobilized in/on porous matrices. The methods used for immobilization were physical adsorption on ceramics and entrapment in glass sol-gel matrices using as alkoxysilane precursors tetraethoxysilane (TEOS) and tetramethoxysilane (TMOS). The immobilization efficiency of the solid enzymatic preparations was about 60%. The immobilized enzymatic preparations were used for hydrolysis of carboxymethyl cellulose (CMC) and cellobiose at different temperature and pH values. The resulted immobilized enzymes had the same optimum pH of 4.0 in the case of cellobiase substrate and a shifted optimum pH towards the less acid side (pH 5.0) in the hydrolysis of CMC. The optimum temperature of entrapped enzyme against CMC was shifted to a lower temperature (40°C) in comparison with the native one (60°C).

Keywords

• cellobiase
• cellulase
• entrapment
• physical adsorbtion
• sol-gel
• trichoderma