Enzymatic hydrolysis of hemicellulose from pretreated Finger millet Check for (Eleusine coracana) straw by recombinant endo-1,4-β-xylanase updates and exo-1.4-β-xylosidase

This study focuses on enzymatic saccharification of hemicellulose part of the pretreated Finger millet straw (FMS) for production of xylose. The variation in the carbohydrate composition of FMS was analysed when subjected to different pretreatments. The recombinant endo-1.4-beta-xylanase (CtXynl 1A) was most active on the FMS pretreated with 1% (w/v) NaOH combined with oven heating at 120 degrees C for 20 min, resulting in a total reducing sugar yield (TRS) of 32 mg/g pretreated biomass. The pretreatment aided in concentrating the holocellulose content from 69.3% of raw powdered FMS to 76.4%. The post-treatment solid biomass yield was 0.36 g/g raw biomass. The two-step optimization of hemicellulose saccharification from the above pretreated FMS with i) endo1.4-beta-xylanase (CtXyn11A) at 55 degrees C and ii) exo-1.4-beta-xylosidase (BoGH43A) at 37 degrees C, both at pH 7.5 by BoxBehnken design yielded the TRS of 70 mg/g pretreated biomass. The percentage conversion of xylan to xylose by CtXynl IA and BoGH43A was 24.7%. (C) 2019 Elsevier B.V. All rights reserved.