Highly retained enzymatic activities of two different cellulases immobilized on non-porous and porous silica particles.

Efficient biological degradation of lignocellulosic biomass is a key step towards developing sustainable biorefineries. One potential approach to improve process efficiency is the use of enzyme immobilization to facilitate reuse of the enzymes. Two different commercial cellulase containing enzyme preparations, termed Cellulases 1 (C1) and Cellulases 2 (C2) for the purposes of this manuscript, were separately immobilized on non-porous silica (S1) and porous silica (S2). The effect of pH, ionic strength and enzyme loading on enzyme stability and activity were all investigated. Immobilized cellulases on S1 showed equivalent enzyme activity as free cellulases, and those on S2 retained 60% enzyme activity. Dissociation of the cellulases from the support after immobilization and during hydrolysis was found to be minimal, suggesting strong enzyme-support interactions. Further, Scanning Electron Microscopy images revealed that S1 and S2 containing immobilized cellulases differentially interact with cellulose, which likely contributes to the observed differences in hydrolysis. [ABSTRACT FROM AUTHOR]