Bioprospecção de fungos filamentosos, perfil enzimático e utilização em resíduos do processamento de café

Abstract

Soils are complex environments hosts a huge biodiversity. The microbiota comprises several taxonomic groups, including bacteria, cyanobacteria, mycorrhizal fungi, micoparasites, plant pathogens and insects, with major degradation function of organic matter. Bioprospecting is a useful tool for discovering new microorganisms applied in biotechnological industrial. The objective this study is make a bioprospecting in soil for obtention one or more fungal strains producers cellulase and xylanase, this way biochemistry feature this enzymes. The fungi were isolated analyzed the surface layer of soil organic matter taken from forest fragments of the Represa do Funil, in Lavras - MG. The technique used for the isolation of fungi was the washing and cultivation particulate soil. In total, 55 fungi were isolated and all have undergone screening of enzymatic activity to cellulase and xylanase through the index test revealed by Lugol solution. The isolates were identified by MALDI TOF and morphology of the vegetative mycelium, and the Aspergillus, Talaromyces, Clonostachys and Fusarium found among them. In the present study aimed to production of these enzymes from arabica and robusta coff ee husks. The pre-selected fungi by bioprospecting Clonostachys rosea, Fusarium solani, Aspergillus japonicus and Penicillium chrysogenum were evaluated by submerged fermentation to check what the best producer of cellulases and xylanases. Between them. C. rosea and A. japonicus were chosen for solid fermentation in the arabica and robusta coffee husks, after enzymatic analysis of these isolates was decided to characterize the crude extract of A. japonicus cultivated in arabica coffee husk. Large production CMCases, xylanase and pectinase were detected. The crude extract was concentrated by ultrafiltration by membrane retention 30 kDa and subjected to molecular exclusion chromatography (Sephadex G 50). Two major fractions were found and evaluated for thermal stability, optimum temperature and pH. The optimum temperature was described as 50 ° C a nd optimum pH in acidic range 3,5 to 6,0. The Pico 1 of the molecular exclusion chromatography was subjected to ion exchange chromatography Q Sepharose for CMCase purification. An endo-1,4-β-glucosidase of approximately 38 kDa was semi purified.