Applicability of Sporotrichum thermophile xylanase in the in situ saccharification of wheat straw pre-treated with ionic liquids

The ionic liquids dubbed as green solvents have been demonstrated to be very effective in pre-treatment of various kinds of biomass for better saccharification. Present study describes ionic liquid stability of thermophilic Sporotrichum thermophile xylanase. It was active and stable in 1-ethyl-3-methylimidazolium acetate IEMIMI[OAc] up to 50% concentration (v/v). The pre-treatment of wheat straw (18-25% (w/w) xylan) with [EMIM][OAc] followed by IL stableS. thermophile xylanase (containing 12 U/mlxylanase activity and 2 U/mlCMCase activity) treatment led to 281 mg reducing sugars (consisting of mainly xylose and xylo-oligosaccharides) per g wheat straw much higher as compared to non-pre-treated. IL stable enzymes enabled simultaneous pre-treatment, saccharification and the intermediate step of washing of residual IL can be eliminated to make the process cost effective. SEM, XRD and FT-IR confirmed the loss of crystallinity by [EMIM][OAc] pre-treatment followed by hydrolytic bond cleavage and deacylation by xylanase in the subsequent step. (C) 2016 Elsevier Ltd. All rights reserved.