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

The utilization of enzymes in industrial processes arouses great interest due to the ease of obtaining and advantages in relation to chemical catalysts. The enzymatic catalysis allowing the increase of the products quality, reduction of production costs and less environmental impact. Proteases secreted by fungi and bacteria have attracted considerable attention due to its great biotechnological potential. These enzymes can be used in different industrial sectors such as the food industry, pharmaceuticals, textile, chemical, effluent treatment, among others. This study aimed to evaluate the production of proteases by microorganisms isolated from industrial effluents. Fungal isolates named BF06, BF09, BF10, BF20, BF22, BF24 and bacterial isolates BF6 and ISO6, were isolated from poultry slaughterhouse effluent located in the city of Rolândia, PR. The proteolytic activity of strains was initially evaluated by the halo formation test in Petri dishes containing (g L-1): skim milk 10, agar 18 and yeast extract 1 in 0.05 M citrate buffer. To quantify the proteolytic activity, the microorganisms were submitted to a submerged fermentation in three different medium compositions: Medium 1: 50 mM citrate buffer, pH 5.0, containing (g L-1): yeast extract 1, casein 10; Medium 2: 50 mM citrate buffer, pH 5.0, containing (g L-1) yeast extract 1 and skim milk 10; and Medium 3: Vogel’s medium + casein (10 g L-1). The flasks were incubated for 72, 96, 120 and 144 hours at 28 °C, 180 rpm. Proteolytic activity was determined using azocasein as substrate after incubation for 40 min at 37 °C. The results showed that BF20, BF6 and ISO6 degraded the milk agar showing halos of degradation. On the other hand, fungal strains BF22 and BF24 did not show proteolytic activity. The BF20 fungus presented greater halo of degradation with an enzymatic index of 2.2. The production of proteolytic enzymes by BF20 was then evaluated by submerged fermentation. The results showed that fermentation using the medium 2 present higher enzymatic activity reaching values of 0.24 U mL-1 min-1. The medium containing casein (Medium 3) also resulted in similar enzyme activity values (0.2225 U mL-1 min-1). On the other hand, Medium 1 resulted in a lower azocaseinolytic activity (0.0394 U mL-1 min-1). According to the results, the BF-20 has great capacity to produce proteolytic enzymes presenting biotechnological potential for future industrial applications. Studies aimed at identifying the strain and purifying the enzyme are in progress.