Abstract
Recycling of cellulase is an important process for decreasing enzyme cost. Cellulase adsorbed onto saccharification residues of lignocellulose, especially onto lignin, is unproductive and can be a significant problem for recycling enzyme. Therefore, a reliable determination of lignocellulose-adsorbed cellulases is necessary. Typically, the amount of adsorbed cellulase has been indirectly calculated by quantifying the cellulase in saccharification liquor using colorimetric methods such as Lowry and bicinchoninic acid (BCA), however, these methods have potential problems of false positive or negative. In this study, the nitrogen contents in the residue based on elemental analysis were applied for the determination of cellulase amount adsorbed onto the residue. It was estimated that approximately 72% of loading cellulase is adsorbed on the residues after 72 h enzymatic hydrolysis of ball-milled Japanese cypress based on the colorimetric method; meanwhile, 31〜36% is adsorbed onto the residues based on nitrogen content. Significant difference was observed between both methods.
