Produção de enzimas fúngicas e avaliação do potencial das celulases na sacarificação da celulose

• Autor(a) principal: Mayrink, Maria Isabel Cristina Batista
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/299
• topic: Enzimas fúngicas; Celulose; Celulases; Fungal enzyme; Cellulose; Cellulases; CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::ENZIMOLOGIA

Different strains of the Trichoderma spp. Endophytic fungi, Aspergillus and Peniciillium were studied for potential production of cellulases and hemicellulases. The fungi were cultured in liquid medium containing sugarcane bagasse and wheat straw as carbon source, and daily aliquots were analyzed in relation to the activities of the production of enzymes, for 13 days. It was also verified the production of enzymes by these fungi in solid state cultivation. Sugarcane bagasse was used as carbon source and support, and the analysis were done every three days for 37 days. The highest activities of cellulase were obtained in liquid medium containing bagasse as carbon source. The highest activities of hemicellulases were in liquid medium with wheat straw as carbon source. The strain T08 (Trichoderma sp. endophytic) highlighted in the production of FPase and endoglycanase and strain TH (Trichoderma harzianum) enzyme with the highest activities of cellobiase and β-glucosidase in a medium sugar cane bagasse as carbon source. The highest activities of hemicellulases such as xylanase and mannanase were produced by strain T03 and T02 (Trichoderma sp. endophytic) respectively, and xylosidase and α-galactosidase by TV (Trichoderma viride) in medium of a wheat straw. It was selected three enzyme extract C011 (Trichoderma sp. T02, cultivated in sugarcane bagasse), C012 (Trichoderma sp. T02, cultivated in wheat straw) and C013 (Trichoderma sp. T08, cultivated in sugarcane bagasse). The activities of maximum endoglycanase and FPase, for all the extracts, were observed at 50 ° C and 40 ° C, respectively, while the optimum temperature for the cellobiase activity ranged between 50 ° C and 65 ° C in different extracts. The cellulolytic activities of selected extracts were characterized and showed maximum activity when incubated at pH 4.5 to 5.5. The saccharification potential of extracts C011, C012 and C013 was evaluated, using Avicel cellulose as substrate. The extracts were applied singly or in combination, and the efficiency of saccharification was evaluated by measuring rates of formation of reducing sugars and glucose formation. The saccharification rates for the extracts for the extracts C011 and C013 were about three times higher, compared to extract C012. There was no significant difference in the rate of saccharification, when the extracts were used in combination.