Analysis of the Lipolytic Potential of Filamentous Fungi Isolated from Some Plants and Soil Samples in Minas Gerais, Brazil

Abstract

Microorganisms have the ability to produce several metabolites, which are widely used in biotechnological processes, including the biological catalysts called enzymes. Among these enzymes, lipases are favored because they perform various catalytic reactions such as hydrolysis, esterification, interesterification and transesterification. This work sought to isolate filamentous fungi from samples collected in Diamantina, Minas Gerais, Brazil, analyze their macroscopic morphological characteristics, determine the effect of temperature on their growth, and verify which organisms are potential lipase producers. From four collection sites, nine fungi were isolated from the leaves and soil of the jabuticaba ( Plinia cauliflora ) tree and three fungi from the Andu bean leaves ( Cajanus cajan ). The macroscopic morphological characteristics of the microorganisms were analyzed. For thermophilic analysis, the twelve isolated fungi and eight obtained from the laboratory bank were cultivated in a solid Potato-Dextrose-Agar medium from 30 °C to 50°C, with intervals of 5°C. The growth rate per hour after 48 hours of development was calculated. For the selection of filamentous lipase-producing fungi, the 20 fungi were cultivated in solid BDA medium at 30 °C for 96 hours, and the enzyme index was calculated. It was found that, of the 20 microorganisms, 95% developed at 30°C, and the highest growth rates were those of fungi 3.2TA, PJ8 and PJ7. At 35°C, 70% of the fungi developed, and the highest growth rates were those of fungi 3.2TA, MB2.2 and P3. At 40°C, 40% of the fungi developed, and the highest growth rates were those of fungi 3.2TA, PJ6 and PJ8. At 45°C, only the PJ6 and PJ12 fungi grew, and no organism grew at 50°C. In the screening for lipase production, the largest growth halo was observed for the 3.2TA fungus from the bank.