Enhancing the enzymatic hydrolysis efficiency of wheat straw pulp residue by prewashing and ferric chloride assisted hydrothermal pretreatment

Abstract

The presence of ash in lignocellulosic materials poses a challenge to achieving optimal conditions for autohydrolysis, thereby impeding efficient enzymatic conversion of biomass. This study investigates the synergistic effects of prewashing and the addition of ferric chloride (FeCl₃) to alleviate the adverse impact of both exogenous and endogenous ash on wheat straw pulp residue (WSPR) autohydrolysis. The findings indicated that as the water ratio (0–2000 w/v) increased and FeCl₃ (20 mM) was added, the removal of xylan and lignin from WSPR enhanced from 64.5 % to 92.4 % and from 20.7 % to 37.5 %, resulting in enhanced enzymatic efficiency of pretreated WSPR from 49.6 % to 90.7 %. The efficacy of these strategies was elucidated via analyses of cellulase accessibility, lignin surface area, particle size, and zeta potential. Furthermore, autohydrolysis of pretreated WSPR yielded a maximum xylooligosaccharide production rate of 171.7 mg/g WSPR. Consequently, the results demonstrated the effectiveness of prewash and FeCl₃ treatments in improving autohydrolysis efficiency and subsequent enzymatic hydrolysis of high ash biomass.