Non-ionic Surfactants and Non-Catalytic ProteinTreatment on Enzymatic Hydrolysis of PretreatedCreeping Wild Ryegrass

摘要

Our previous research has shown that saline Creeping Wild Ryegrass (CWR),Leymus triticoides, has a great potential to be used for bioethanol production because of itshigh fermentable sugar yield, up to 85% cellulose conversion of pretreated CWR. However,the high cost of enzyme is still one of the obstacles making large-scale lignocellulosicbioethanol production economically difficult. It is desirable to use reduced enzyme loadingto produce fermentable sugars with high yield and low cost. To reduce the enzyme loading,the effect of addition of non-ionic surfactants and non-catalytic protein on the enzymatichydrolysis of pretreated CWR was investigated in this study. Tween 20, Tween 80, andbovine serum albumin (BSA) were used as additives to improve the enzymatic hydrolysisof dilute sulfuric-acid-pretreated CWR. Under the loading of 0.1 g additives/g dry solid,Tween 20 was the most effective additive, followed by Tween 80 and BSA. With theaddition of Tween 20 mixed with cellulase loading of 15 FPU/g cellulose, the celluloseconversion increased 14% (from 75 to 89%), which was similar to that with cellulaseloading of 30 FPU/g cellulose and without additive addition. The results of cellulase andBSA adsorption on the Avicel PH101, pretreated CWR, and lignaceous residue ofpretreated CWR support the theory that the primary mechanism behind the additives isprevention of non-productive adsorption of enzymes on lignaceous material of pretreatedCWR. The addition of additives could be a promising technology to improve the enzymatichydrolysis by reducing the enzyme activity loss caused by non-productive adsorption.