Inhibitory Effect of Additives on Cellulase Adsorption Mediated by Hydrophobic Interaction

Reduction in the cost of the cellulase used for saccharification of cellulose is essential to commercialize bioethanol and bio-chemicals derived from cellulosic biomass. Utilization of additives such as proteins and surfactants to prevent non-productive adsorption of cellulase on lignin can reduce the use of cellulase. However, the action of these additives is not sufficiently understood. This study investigated the effects of additives on cellulase adsorption on lignin using graphite as a hydrophobic substance to evaluate the hydrophobic interaction between cellulase and lignin. Inhibition of enzymatic hydrolysis of filter paper was observed by addition of graphite, indicating hydrophobic interaction between cellulase and graphite. Addition of bovine serum albumin (BSA) and Tween80 enhanced enzymatic hydrolysis in the presence of graphite. In contrast, addition of polyethylene glycol (PEG) in the presence of graphite had no positive effect. The adsorption amounts of BSA and Tween80 were larger than that of PEG. Therefore, the effects of additives on cellulase adsorption mediated by hydrophobic interaction are considered to reflect the differences in adsorption amounts of additives on graphite.