Anais do Congresso Paranaense de Microbiologia
IV Congress of Microbiology in Paraná

Cheese producing industries are responsible for moving the economy significantly. To maintain this production chain, it is necessary to use fungi in the production of this food, as these are microorganisms capable of presenting proteolytic potential as they are enzyme producers, acting on casein in the coagulation of milk. The objective of this project was to isolate and select potentially chymosin-producing fungi from the biodiversity present in a subregion of the South of Minas/MG in order to build a mycothek of the research group on Physiology and Biotechnology of Microorganisms at the State University of Minas Gerais (UEMG). The isolations were carried out with 3 samples – buffalo teat surface biofilm, buffalo milk and buffalo feces – collected on the rural property Sítio Pérola, located on MG 466 Km 18 highway, in the municipality of Alpinópolis, and 2 samples of ruminal fluid from Nelore and Tabapuã cattle, collected at the Federal University of Lavras (UFLA). The samples were submitted to serial dilution in saline 0.85% (w/v) sterile. A 100 μL aliquot of the 10-1 and 10-3 dilutions were plated on potato dextrosed agar (PDA) by spread plate, in duplicate. The culture medium was added with 0.5mL of ampicillin to inhibit bacterial growth. From the growth of a mixed population on these plates, each colony obtained was isolated, by subculture, in PDA. Afterwards, the isolates were submitted to coagulation test in milk-agar medium containing 2% milk. The samples were incubated for 4 to 7 days at 25°C. Positive tests were those that showed a translucent halo around the colony isolated on milk-agar. Then, 25 filamentous fungi and 6 yeasts were isolated from 5 samples. From these isolates, 15 filamentous fungi were positive: 3 from Atabapuã bovine ruminal fluid sample, 5 from a Nelore bovine ruminal fluid sample, 2 from a buffalo teat surface biofilm sample, 3 from a milk squirt buffalo sample and 2 from buffalo feces sample. The strains that showed positive results are under analysis. All yeasts were negative. It was observed that the use of filamentous fungi for the production of cheese is more convenient and effective, since they presented greater potential for coagulation of casein.