(364b) The Effects of Cationic Polyelectrolyte On the Pretreatment and Enzymatic Hydrolysis of Corn Stover

Lignocellulose is the most abundant renewable biomass and the potential substrate for ethanol production. The costly pretreatments and large consumption of enzymes are needed to reach high cellulose conversion. Lignin, as one of major cell wall components, is considered as the barrier to enzymatic hydrolysis by blocking cellulase from productively being adsorbed. The removal or effective modification of lignin is required for efficient pretreatment process. In this study, the effects of cationic polyelectrolyte, poly-(dimethyldiallylammonium chloride) (PDAC), on alkaline pretreated corn stover were investigated. Structural study by Scanning Electron Microscopy (SEM) imaging revealed particles morphology on cell walls of pretreated corn stover. These particles were confirmed to contain lignin by Confocal Laser Scanning Microscopy (CLSM) and Transmission Electron Microscopy (TEM) imaging. Chemical compositions of pretreated corn stover at different alkaline and polyelectrolyte concentrations were analyzed. Higher polyelectrolyte concentration in the pretreatment resulted in higher lignin retention. Evaluation of enzymatic hydrolysis showed the enhancement of cellulose and hemicellulose conversion after polyelectrolyte pretreatment. PDAC was proposed to facilitate cellulose disruption and lignin redistribution via its interaction with lignin, which significantly modified biomass morphological properties, such as increased porosity and improved accessibility of cellulose surface.