(582cw) Immobilization of Cellulase On a Silica Gel Substrate Modified Using a 3-Aptes Self-Assembled Monolayer

Cellulase was immobilized onto silica gel surfaces which was pretreated with (3-Aminopropyl) triethoxy-silane (3-APTES). Glutaraldehyde was used as a cross-linker between the cellulase layer and the 3-APTES layer. The hydrolysis of the carboxymethylcellulose sodium salt (CMC) solution made in pH=6 acetate buffer was investigated using the free and immobilized cellulase at different temperatures. Storage and pH stability were also investigated. The amount of protein in the enzyme solution was determined by the fluorescamine protein assay. As a result, cellulase was successfully immobilized on the modified silica gel surface, and little enzyme desorption was observed during the hydrolysis of the CMC solution. The highest activities of both immobilized and free cellulase appear at 50°C. The specific activity of the immobilized cellulase is 7% compared to the similar amount of free cellulase. Significant activity over multiple reuses was observed. The seventh batch achieved 82% activity of the initial batch, and the fifteenth batch retained 31% (with little decrease through 26 cycles of reuse). It was observed that the immobilized cellulase retained 48% of its initial activity after 4 days, and 22% even after 14 days.