Improved sugar recovery from enzymatic hydrolysis of Miscanthus sinensis by surfactant-mediated alkaline pretreatment

Surfactants play a vital role in the removal of lignin and subsequent enzymatic saccharification of lignocellulosic biomass. In this work, a surfactant-mediated alkaline pretreatment (SMAP) with short residence time and low NaOH loading has been successfully developed for enhancing enzymatic hydrolysis of a potential energy plant, Miscanthus sinensis, and evaluating its potential as a feedstock for biofuel production. As compared to individual alkaline pretreatment (AP), the SMAP process resulted in significantly more hemicellulose removal, more efficient delignification, higher cellulose content (55% vs. 51%), and stronger morphological disruption of the pretreated stalks, making them more accessible to cellulases and/or microorganisms. As a result, SMAP produced a significantly higher sugar yield of 402.5 mg/g than the control and AP group (287.8 mg/g) (p < 0.05). Among the tested surfactants, Tween 40 was identified as a potential candidate for SMAP of biomass wastes. SMAP with mild conditions (i.e., 121 °C, 10 min, 1.0% NaOH, 1.0% Tween 40) gave the highest sugar yield of 566.0 mg/g, which were 6.5-folds greater than the raw stalk. These demonstrations for using SMAP to achieve enhanced lignin removal and sugar recovery from biomass highlight its strong application potentials of improving bioconversion of lignocellulosic biomass like Miscanthus sinensis, hence making this crop a valuable energy plant.