Sulphite addition during steam pretreatment enhanced both enzyme-mediated cellulose hydrolysis and ethanol production

Abstract Sulphite addition during steam pretreatment of softwoods under acidic, neutral and alkaline conditions was assessed to try minimize lignin condensation. Although neutral/alkaline resulted in effective sulphonation, non-uniform size reduction observed. In contrast, acidic sulphite treatment at 210 °C for 10 min homogenous particle water-insoluble component that 62% carbohydrate 33% lignin. This carbohydrate-rich substrate readily hydrolyzed fermented which indicated the lack fermentation inhibitors steam-pretreated whole slurry. The use high solid loading (25% w/v) a hydrolysis yield 58% an enzyme 40 mg protein/g glucan efficient (46.6 g/L ethanol). improved both enzymatic slurries. Graphical