Bioprospecção de fungos filamentosos isolados de cavernas brasileiras produtores de pigmentos

Abstract

The objectives of this study were to select and identify pigment-producing fungi isolated from Brazilian caves, evaluate the growth and pigment production by selected fungi in four different media, characterize the main colored metabolites in their extracts and dry the colored extractsusing three different adjuvants through spray drying technique. Among the tested fungi, twelve were selected and identified as:Aspergillus sydowii (GMA3) (1) A. aureolatus (E.2.5) (2), A. keweii (CF292) (2), Penicillium flavigenum (E.2.4) (3) P. chermesinum (102) (1), Epicoccum nigrum (185A) (1), Lecanicillium aphanocladii (ONI5) (1) and Fusarium sp. (FPW) (1). The pigment production by these fungi was influenced by medium composition. The complex media seemed to favor a higher growth and production of pigments. In this study, we identify three colored compounds: oosporeina, orevactaene and dihydrotrichodimerol in extracts of L. aphanocladii (ONI5),E. nigrum (185A) and P. flavigenum (E.2.4), respectively. Furthermore, it was observed that theextract ofL. aphanocladii (ONI5)and P. flavigenum (E.2.4)showed phytotoxicand growthinhibitory effects against aquatic plant Lemna minor. Among the fungi studied, colored extracts of three species (E. nigrum (185A), P. flavigenum (E.2.4) and A. keveii (CF292)) were dried by spray drying technique. The addition of three adjuvants (maltodextrin, modified starch and gum arabic) resulted in fine powders with low moisture content and water activity. Moreover, all studied adjuvants ensured high color retention and product recovery during the drying process.Therefore, the results indicate that filamentous fungi isolated from Brazilian caves can be new sources of natural pigments and their extracts can be dried by spray drying technique to facilitate the storage and marketing of these dyes.