Amylases hydrolyze 1,4-linked alpha-D-glucosyl residues of starch to D-glucose, maltose and maltooligosaccharides. Endoamylases hydrolyse randomly alpha-1,4 linkages in the starch molecule, and exoamylases act on the nonreducing end of oligosaccharides and polysaccharide chains. Amylases can be obtained from several sources, such as plants, animals and microorganisms but enzymes from microbial sources are commonly used in pharmaceutical, fine-chemical, bakery, brewery, cellulose and paper industries. The aim of this work was to study amylases of a new fungus isolated in our laboratory from Mangifera indica L, identified as Aspergillus niveus. Amylase activity was assayed at 60°C using 0.5% soluble starch in 0.10 M acetate buffer, pH 5.0. The reducing sugar released was measured by the 3,5' dinitrosalicilic acid method (Miller 1959) using glucose as a standard. One unit of amylase activity (U) was defined as the amount of enzyme that released 1mol of reducing sugar/minute. Protein was determined by the Lowry method. The fungus exhibited excellent amylase production when grown for 72 h at 40ºC in Khanna medium, initial pH 6.5, under standing conditions. Among several carbon sources the highest levels of amylolytic activities were obtained from triturated maize (200 U/mL), but oatmeal, rice straw, maizena®, soluble starch, maltose, wheat bran, glucose and penetrose were also excellent inducers, with 173, 144, 111, 106, 87, 86, 86, and 85 U/mL, respectively. On the other hand, sucrose, cob corn, arabinose and lactose were poor inducers of amylases. The hydrolysis products of the amylases obtained from cultures on soluble starch were analyzed by thin layer chromatography. Glucose, maltose and maltotriose were detected after 2h of enzymatic assay, suggesting the presence of at least a glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) and alpha-amylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.1).

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