Alkaline Peroxide Pretreatment of Waste Lignocellulosic Sawdust for Total Reducing Sugars

- The surge in the oil prices, increasing global population, climate change, and waste management problems are the major issues which have led to the development of biofuels from lignocellulosic wastes. Cellulosic or second generation (2G) bioethanol is produced from lignocellulosic biomass via pretreatment, hydrolysis, and fermentation. Pretreatment of lignocellulose is of considerable interest due to its influence on the technical, economic and environmental sustainability of cellulosic ethanol production. In this study, furniture waste sawdust was subjected to alkaline peroxide (H2O2) for the production of reducing sugars. Sawdust was pretreated at different concentrations from 1-3% H2O2 (v/v) loadings at a pH of 11.5 for a residence time of 15-240 min at 50, 75 and 90 celcius. Optimum pretreatment conditions, such as time of reaction, operating temperature, and concentration of H2O2 , were varied and evaluated on the basis of the amount of total reducing sugars produced. It was found that the changes in the amount of lignin directly affected the yield of reducing sugars. A maximum of 50% reduction in the lignin composition was obtained, which yielded a maximum of 75.3% total reducing sugars yield and 3.76 g/L of glucose. At optimum pretreatment conditions of 2% H2O2 loading at 75 celcius for 150 min, 3.46 g/L glucose concentration with a 69.26% total reducing sugars yield was obtained after 48 hr. of the hydrolysis process. Pretreatment resulted in lowering of crystallinity and distortion of the sawdust after the pretreatment, which was further confirmed by XRD and SEM results.