| Congresso Brasileiro de Microbiologia 2023 | Resumo: 463-1 | ||||
Resumo:Amylases are frequently and widely used in industry because of its low cost of production and biochemical characteristics, and because they hydrolyze starch. However, most of the amylases described in the literature are not thermotolerant, making their use in processes that occur at high temperatures unfeasible. Many industries use processes at high temperatures, including textile industry in “desizing” process, brewing industry, paper industry, and biofuel industry, for example. In this context, studies searching for filamentous fungal strains focused on the production of thermotolerant enzymes in order to improve the industrial applications of these biocatalysts at high temperatures are very important. Therefore, the present study isolated filamentous fungi from soil of ironstones outcrops in Corumbá-MS. Soil samples were serially diluted (10 -1 to 10 -4) in salt solution 0.85% and inoculated in Petri dishes containing potato dextrose agar (PDA) medium with 1 mg/mL ampicillin. The strains were cultured until pure strains were obtained. Of the 34 filamentous fungi evaluated, the isolate number 21 showed potential for amylase production and was molecularly identified as Rhizopus oryzae, using the primers ITS1 and ITS2. The amylase activity was determined with the 3,5-dinitrosalicylic acid (DNS) method. Optimal pH of enzyme activity was determined by evaluating enzyme activity at 50°C and at different pH values in range 3.0–8.0, with increments of 0.5, using the McIlvaine buffer. The optimum temperature of enzyme activity was determined by measuring the enzymatic activity within the range of 30–85°C, with increments of 5 °C, at the optimum pH. Results of biochemical characterization of the enzyme production by isolated R. oryzae, showed that optimal enzymatic activity is at pH 5.0 and at 75°C with 65.27 U/g of amylolytic activity. These characteristics make possible the application of this enzymatic extract in industrial textile processes for “desinzing” of fiber that occur between 60°C-80°C, for example. Palavras-chave: Amylases, ironstones outcrops, fungal strains, biochemical characteristics Agência de fomento:CAPES | |||||