Utilização de celulases de leveduras para produção de bioetanol de segunda geração

Abstract

The production of lignocellulosic ethanol is emerging being an important technology for the sustainable development. For the utilization of the lignocellulosic material is necessary change in the physical and chemical barriers of the cohesive association of the main components of biomass, that difficult the hydrolysis of cellulose and hemicellulose to fermentable sugars. The pretreatment changes the lignocellulosic structure in order to facilitate the enzyme activity and therefore generate sugars for the fermentation process. One of the factors that limited the enlargement of this technology is the high cost of the microbial enzymes involved in this process. The objectives of this work were the isolation of cellulolytic yeast from soil and evaluate the hydrolytic capacity of microbial enzymes in the lignocellulosic substrate. Cellulolytic yeasts were isolated from soil of Brazilian savannah and Amazon region. The enzymatic saccharification of sugar cane bagasse pretreated with diluted sulfuric acid (H2SO4) was also evaluated. A total of 123 yeast was isolated, 103 from Cerrado and 20 from Amazonia region, and 17.47% and 55% were cellulose producer, respectively. The better isolate was selected to enzyme quantification and presented β-glycosidase activity higher than endo and exoglucanase activities. The enzymatic extract was efficient to convert 16% of cellulose approximately after 72 hours of incubation. The results showed the importance of isolating indigenous microbial strains able to produce enzymes of biotechnology interest, such as biofuel production.