Mechanistic Insights into Morphological and Chemical Changes During Benzenesulfonic Acid Pretreatment and Ssf Process for Ethanol Production

The hydrotropic benzenesulfonic acid (BA) pretreatment showed outstanding ability in lignin/hemicellulose removal under mild conditions as well as superior glucose yield during enzymatic hydrolysis. In this work, the BA-treated substrates were employed for simultaneous saccharification and fermentation of ethanol for the first time. The ethanol yield of ~50.36% was attained at 10% solids loading and 47.45 g/L concentrations of ethanol accumulated at 30 % solids loading. The dramatic improvements could result from the deconstruction of cell walls, including lignin and hemicellulose removal and cellulose exposure, which were evidenced by fluorescence microscope and confocal Raman microscopy spectra. Additionally, the changes in lignin structure features during the BA pretreatment were first identified by GPC and NMR for thorough comprehension the inherent chemistry of lignin during the pretreatment. In summary, this study tried to probe the possibility of BA-treated Miscanthus for SSF process and unveiled the mechanism of the near-complete enzymatic hydrolysis efficiency.