The Deconstruction of the Lignocellulolytic Structure of Sugarcane Bagasse by Laccases Improves the Production of H2 and Organic Acids.

The production of biofuels using sugarcane bagasse (SCB) as substrate can be considered an environmentally friendly approach, due to the possibility of combining energy production with the reuse of agroindustrial wastes. This study was undertaken to explore the applicability of a new extract with the enzymes (Lacmix) isolated from Chaetomium cupreum for SCB pretreatment. Lacmix was more active at pH of 2.2 to 4 and 50 to 60 °C. Further, the individual and mutual effects of SCB concentration (6.6 to 23.4 g L- 1), enzyme concentration (0.066 to 0.234 U L- 1), and incubation time of the SCB with Lacmix (19 to 221 min) on SCB pretreatment were evaluated using a response surface methodology and central composite design. The optimized conditions were 23.4 g L- 1 SCB, 0.234 U mL- 1 laccases, and 2.44 h resulting in 547 ± 108 mg L- 1 of total sugars. This value agrees with the predicted value (455 ± 41 mg L- 1) by the statistical model. Through the SCB pretreated with Lacmix fermentation, 96.1% more H2 and 22.5% more organic acids were observed compared to SCB without pretreatment. Therefore, laccases improve delignification, maximizing biomass fermentation for biofuel production.