Isolation of High Amylase-producing Filamentous Fungi from the Caatinga: Standardization of the Culture Conditions and Amylase Activity from Penicillium sp. L1

Abstract

Microbial amylases are commercially available and have almost completely replaced the chemical hydrolysis of starch in various industrial processes. Microbial amylases have a wide range of applications because they are more stable than amylases obtained from plants and animals. This work sought to isolate filamentous fungi from three different samples collected in Janaúba, in the north of the state of Minas Gerais, to select a filamentous fungus that produces amylases, to determine the best cultivation conditions for the selected fungus for amylase production, and to analyze the biochemical characteristics of the enzyme. After collecting the samples for the isolation of filamentous fungi, the macroscopic morphological characteristics of the fungi, the microculture for the determination of the possible genus, and the effect of temperature on fungal growth were determined. The screening of the fungi was performed in a submerged medium to characterize the amylase-producing microorganism through the analysis of the physicochemical parameters of the medium concerning the source of nitrogen, the type of salt solution, and the source of carbon, as well as to optimize the production of amylase. The biochemical characterization of the enzyme was performed. The fungus Penicillium sp. (L1) was selected, and the greatest production of amylase was observed in submerged Carvalho-Peixoto (CP) medium associated with Wesson salts using yeast extract and starch as nitrogen and carbon sources, respectively, at 30 ºC, over seven days. The optimum temperature and pH of the assay were 60 ºC and 5.5, respectively. Thus, the northern region of Minas Gerais was an excellent source for the strains that exhibited a potential for the production of amylase for use in industry, indicating that the fungus Penicillium sp. (L1) and the amylase produced have a relevant potential for biotechnological applications.