This study aims to improve enzymatic sugar production from dilute sulfuric acid-pretreated barley straw
for acetone–butanol–ethanol (ABE) fermentation. The effects of additive xylanase and surfactants (polyethylene
glycol [PEG] and Tween) in an enzymatic reaction system on straw hydrolysis yields were investigated.
By combined application of 2 g/100 g dry-matter (DM) xylanase and PEG 4000, the glucose yield
was increased from 53.2% to 86.9% and the xylose yield was increased from 36.2% to 70.2%, which were
considerably higher than results obtained with xylanase or surfactant alone. The ABE fermentation of
enzymatic hydrolysate produced 10.8 g/L ABE, in which 7.9 g/L was butanol. The enhanced sugar production
increased the ABE yield from 93.8 to 135.0 g/kg pretreated straw. The combined application of xylanase
and surfactants has a large potential to improve sugar production from barley straw pretreated with
a mild acid and that the hydrolysate showed good fermentability in ABE production