Corncob-based biorefinery: A comprehensive review of pretreatment methodologies, and biorefinery platforms

The xylan richness and comparatively lower extractives and ash, make the corncob lignocellulose an excellent source for many biorefinery products and objectives. The unique packing of lignocellulose material in corncob makes it susceptible to different pretreatment approaches that are less effective on other types of biomass feedstocks. More specifically, after pretreating corncob, up to 99% delignification, 100% hemicellulose solubilization, and around 95% cellulose recovery can be achieved. Accordingly, corncob-derived chemical platforms have found many applications ranging from conventional use to newer products like supercapacitors. Platform sugars and ethanol have been the major products derived from corncob's cellulose and hemicellulose, whereas the production of xylooligosaccharides is the second most reported objective. Corncob lignin is mostly valorized for its phenols. Traditional and emerging pretreatment approaches, were reported, and in some reports, corncob-lignocellulose is valorized without a pretreatment. The data reported over the past fifty years on the corncob pretreatment in the SCOPUS database was compiled and analyzed throughout this review. The efficiency of different pretreatment methodologies and their effect on downstream yields were compared in detail.