Hydrophilicity Regulation of Styrene-Based Copolymers to Promote the Enzymatic Saccharification Efficiency by Dually...

Nonproductive adsorption behavior of residual lignin on cellulase has long hindered lignocellulosic biomass enzymatic saccharification. In this study, a strategy of hydrophilicity regulation of styrene-based copolymers was developed to improve the enzymatic saccharification efficiency by specifically acting on cellulases and blocking residual lignin. Styrene-based copolymers with 2-acrylamido-2-methylpropanesulfonate (ST-co-AMPS or SA), varying in molecular weight and hydrophilicity, were synthesized. At pH 4.8 and 10 FPU/glucan cellulase dosage, adding 0.1 g/g-substrate SA8-32 (initiator dosage = 8%, ST% = 32%) boosted the sugar yield from 45.6 to 83.4%. When the pH increased to 5.5, SA4-16 addition further raised the yield to 94%. Quartz crystal microbalance and atomic force microscopy analyses revealed that ST-co-AMPS directly interacted with cellulase to form complexes while also blocking residual lignin. Fluorescence spectrometer analysis showed SA-cellulase complexes reduced nonproductive adsorption via hydrogen bonding and van der Waals forces. Given the demand for efficient lignocellulosic bioconversion in sustainable biorefineries, ST-co-AMPS shows great potential as an additive to enhance lignocellulose enzymatic saccharification.