ENSILAGE EFFECT ON THE 2ND GENERATION BIOETHANOL PRODUCTION FROM SWEET SORGHUM BAGASSE

摘要

The bioethanol production chain which uses sweet sorghum (Sorghum bicolor L. Moench) as rawmaterial is characterized by a high amount of by-products, in particular the bagasse obtained after the juice extractionand the vinasse from the juice fermentation. The article is specifically focused on the second generation bioethanolproduction from lignocellulosic residue as sweet sorghum bagasse. Several field trials were conducted to selectvarieties of sweet sorghum to maximize biomass production under conditions of low agronomical inputs and reducedirrigation. The stems of SUCRO 506 variety were chopped and ensiled in plastic barrels under anaerobic conditionswith different addictives to allow the sugar preservation. The bagasse samples, obtained from the ensiled materialcrushed after 90 and 180 days, were analyzed for the content of fibers by using different extraction techniques. Thenthe samples were subjected to enzymatic hydrolysis and fermented with the M861/10a Saccharomyces cerevisiaestrain for the production of 2nd generation bioethanol. Single samples were analyzed by gas chromatography and theglucose and ethanol percentage yields were estimated. Improvements of the glucose and ethanol yield were observedwith respect to the different ensiling techniques, and statistically significant differences were found as a function ofensiling time.