Isolamento de fungos filamentosos em sistema aberto de tratamento do soro do leite por microalgas

Abstract

Whey, a by-product of cheese production, has a high polluting potential if disposed of improperly. Thus, bioremediation in open systems is a way to treat this effluent, since it does not require asepsis of the effluent and allows contamination by exogenous microorganisms that can provide a positive co-culture with other microorganisms. Therefore, this work isolated and characterized exogenous contaminating filamentous fungi in milk whey during its treatment in an open system with the microalgae Tetradesmus sp. in transparent acrylic vessel reactors (PoliControl©) with different organic loads (1 and 4% v/v) and light intensity of 100 µmol photons m-2 s-1 in batch for 7 days. The identification of contaminating fungi occurred using Agar Sabourard, PDA (Potato Dextrose and Agar) and Nutrient Agar media with different dilutions, made in 0.1% peptone water using the spreading and striation technique and every 3 days, the microbial growth was followed by counting colony forming units (CFU). It was proved that the open treatment system presents exogenous contaminants and that the feedback causes a decrease in the concentration of microbial cells. Furthermore, six distinct filamentous fungi were isolated and presented characteristics (morphological and microscopic) that possibly make them belong to the genera Trichophyton, Cladosporium, Epidermophyton, Chrysosporium, Nigrospora and Penicillium, being a molecular characterization necessary to confirm the genus and species of these microorganisms.