Effects of nonionic surfactant on enzymatic hydrolysis of used newspaper

Abstract

Effects of five types of nonionic surfactant having a polyoxyethylene glycol (POG) group on enzymatic hydrolysis of used newspaper were studied. The surfactants examined in this work always enhanced the saccharification. The optimum surfactant concentration was 0.05% (wt/substrate wt) in the case of POG(21) sorbitane oleic ester. Among the surfactants, POG phenyl ether types showed the highest enhancement effect, for example, with two times higher conversion at 80 h than that without surfactant. Using POG nonylphenyl ether series, the effects of surfactant were considered from the point of the HLB (hydrophile-lypophile balance) value. The GFC (gel filtration chromatography) analysis of free enzyme quantity were also done to study the effect of surfactant on enzyme adsorption onto substrate. As the HLB value increased, the free enzyme quantity and the conversion both increased. It appears that surfactants help the enzyme to desorb from the binding site on the substrate surface after the completion of saccharification at that site.