It has been become a well-established fact that addition of surfactants to enzymatic hydrolysis of lignocelluloses can increase the conversion of polysaccharide fraction into fermentable sugars (Kumar and Wyman, 2009b). In the present study, although significant increase in hydrolysis yield was obtained for WS pretreated by dilute
acid in combination with Tween 20 (Table 3), there was considerable amount of lignin left in WIS obtained after Tweenassisted dilute acid pretreatment (Table 1), which would negatively affect enzymatic hydrolysis.
Based on the proposed mechanisms
on the surfactant effect on pretreatment and enzymatic
hydrolysis, enhanced enzymatic convertibility could be expected
if Tween 20 was added during enzymatic hydrolysis of Tweentreated
lignin-containing substrate. Following experiments were
carried out to investigate if surfactant could improve the enzymatic
conversion of surfactant-assisted dilute acid pretreated
WS. Hydrolysis experiments were performed on WS pretreated at
conditions enabling maximum cellulose digestibility (2% sulfuric
acid combined with 1% Tween 20), which gave the highest yield
of glucose and xylose (Table 3). For comparison, the effect of surfactant
on enzymatic hydrolysis of WS pretreated by individual
2% acid was also investigated.