(587p) Effects of Dilute Sulfuric Acid Pretreatment Conditions On Enzymatic Hydrolysis of Panicum Maximum: A Novel Raw Material for Bioethanol Production in Colombia

Production of ethanol from lignocellulosic biomass involves three main steps: pretreatment, enzymatic hydrolysis and fermentation. Pretreatment of the biomass is needed to make available cellulose to enzymes during enzymatic hydrolysis. Two problems during pretreatment are: low solids concentration used and degradation of hemicellulose and lignin to inhibitor compounds. Those compounds decrease the glucose yield at enzymatic hydrolysis step. In this work, the effect of high solids loading at pretreatment was studied. Panicum maximum, a forage grass, was used as lignocellulosic biomass. This is considered a potential biomass in Colombia with a dry biomass yield of 40 tons/ha/year and 7.4 million hectares available to biofuels. Pretreatment selected was diluted sulfuric acid and conditions evaluated were: sulfuric acid concentration (0.5, 1 and 1.5% w/v) and solids loading (5, 8.5 and 12% w/w) at 130^oC and 60 minutes. Subsequently, pretreated biomass digestibility (g glucose/ g dry pretreated biomass) was determined with enzymatic hydrolysis using cellulase and β-glucosidase at 50^oC and a pH 4.8 during 48 hours. Response surface method was used to design the experiments matrix to pretreatment step. Best conditions of diluted acid pretreatment were: 1.5% w/v and 12% w/w with a biomass weight loss of 40% and release of 0.35 g of glucose/ g dry pretreated biomass.