Screening of filamentous fungi from Brazilian rainforests for enzyme production

Screening of new microbial strains for enzyme production is a key step in the improvement of industrial bioprocesses. The objective of this work was to isolate fungal strains from Brazilian rainforests and to evaluate their potential to produce industrial enzymes by solid state fermentation. First, 131 strains of filamentous fungi were isolated from Amazon rainforest and Atlantic rainforest regions. Strains selected by simple plate assay had their ability to produce lipase and tannase by fermentation of wheat bran evaluated. Maximum enzymatic activity of 1.35 and 18.7 U/mL were reached by lipase and tannase, respectively. The strain IB28a was identified by molecular and morphologic techniques as Colletotrichum sp. Lipase produced by this strain reached specific activity of 25.97 U/mg and showed Km and Vmax of 6.3 and 19.5, respectively. Lipase from Colletotrichum sp. had an optimal temperature range of 25 to 35°C and optimal pH range of 6.5 to 7.0. Moreover, the enzyme was stable after 1 h at temperatures up to 40°C and after 24 h at pH 6.5.