The promotional effect of water-soluble extractives on the enzymatic cellulose hydrolysis of pretreated wheat straw.

•Water-soluble extractives from wheat straw enhance enzymatic cellulose hydrolysis.•Promotional effect from unpurified extract, no additional processing required.•Possibly positive effect on enzyme deactivation and cellulose accessibility.•Up to 85% relative increase in digestibility of organosolv pretreated pulp.•Promotional effect caused by components larger than 1kD, possibly proteins.