THE MECHANISM ON IMPROVING ENZYMATIC DIGESTIBILITY OF PRETREATED LIGNOCELLULOSE BY ADDING SULFONATED LIGNIN

摘要

It has been proved that the addition of sulfonated lignin(SL)could effectively improve the enzymatic digestibility of alkali-or acidic bisulfite-pretreated lignocellulosic materials.However,the interaction between cellulase and SL is still unclear.In this work,the interactions between SL and cellulase with various proportions were investigated by means of FT-IR and fluorescence spectra.The influence of SL addition on cellulase adsorption on milled-wood lignin and substrate enzymatic hydrolysis was monitored using a quartz crystal microgravimetry(QCM).According to the FT-IR and fluorescence spectra,it is of great possibility that SL combined together with cellulase to form SL-cellulase complex.QCM analysis showed that SL addition had little effect on the enzymatic hydrolysis of lignin-free substrate such like cellulose,but dramatically decreased the adsorption amount of cellulase on lignin.Therefore,the improved enzymatic digestibility of pretreated lignocellulose by adding SL is mainly due to the reduction of non-productive adsorption of cellulase on lignin in substrate.