Biofilm Formation by Filamentous Fungi Recovered from a Water System

Filamentous fungi have been constantly recovered from diverse aquatic environments including drinking water distribution systems. Although most of the works are focused on the study of planktonic form, recent researches have shown that fungi develop biofilm within these systems. In this study, Aspergillus sp. (section Nigri), Aspergillus sp. (section Flavi), Alternaria sp., Botrytis sp., Cladosporium sp., and Penicillium sp. recovered from water biofilms were used to evaluate their capability to grow as biofilms under laboratorial conditions. Morphological and physiological characteristics were analysed using image analysis and biomass and cell activity estimation. All six isolates were able to form biofilm, though different patterns of development were observed. Only Alternaria sp. formed biofilm in water over 24 h of analysis. MEB was shown to be the best culture media for biofilm formation. A direct correlation between biomass and cell activity was not observed, but biomass values and morphological parameters, that is, monolayer and EPS production, were directly correlated. Thus, the results present here highlight the capability of fungi to form biofilms and the emergent necessity to standardize methods for further research in this area.