Prospecção e caracterização de linhagens fúngicas produtoras de complexos enzimáticos lignocelulolíticos provenientes de resíduos de ambiente canavieiro

Abstract

The bioenergetic potential of Brazil is represented largely by the alcohol and sugar sector, because the sugar-cane is a source of renewable and abundant energy. Besides the use of the sugar-cane juice for ethanol production and use of bagasse for energy purposes, the polysaccharides (mainly cellulose) can be released by enzymatic hydrolysis to be fermented into ethanol and other products with higher added value. The high cost of cellulolytic enzymes represents the biggest challenge to the viability of the process. Currently, the fungi are the main producers of industrial enzymes lignocellulolytic. The Knowledge of the diversity and potential of the fungi from the environment is still a little explored. Therefore, in this study, filamentous fungi were isolated and selected from sugarcane soil environment of the northern region of Minas Gerais state, with the aim of obtaining strains with potential for production of enzymes lignocellulolytic. The samples were collected from soil and waste of sugar cane in post-drought and post-rains periods. The Samples were collected at pre-selected points strategically for a total of 16 samples. 230 morphotypes were isolated of which 124 identified as cellulolytic, through qualitative tests, and of these 5 also hemicellulolytic and 7 lignolytics. The fungus Trichoderma reesei RUT C-30 ATCC 56765 and Aspergillus awamori B.361 U2/1 were used as reference of producer strains of cellulases and hemicellulases. In relation to the quantitative enzymatic analysis, were tested in submerged fermentation in mechanical shaken flasks and in solid state fermentation in stationary culture flasks, 19 morphotypes cellulolytic. Of these, five morphotypes were identified taxonomically, 2 genus and 3 species, namely: Coriolopsis sp. (Basidiomycete), Aspergillus cf. phoenicis, Penicillium raistrickii; Penicillium angulare and Penicillium variabile. In submerged culture with lactose, the Coriolopsis sp. presented the highest endoglucanase activity (CMCase 7.8946 IU/ mL), and the Penicillium angulare and Penicillium raistrickii, increased activity FPase, 0.7103 and 0.6631 IU/ mL respectively. The Penicillium variabile stood out due to its higher activity -glucosidase 1.3356 IU/ mL, greater than the Aspergillus awamori control in the same cultivation conditions Hemicellulosic activity (xylanase) was better presented by Penicillium raistrickii, 5.2161 IU/ mL. Sugarcane bagasse is presented as a good substrate and inducer in culture submerged for CMCase activity produced by Penicillium angulare and Penicillium raistrickii as well as for all analysed enzymes produced by Coriolopsis sp., compared with cultivation with lactose or wheat bran