ISOLATION, CHARACTERIZATION OF ASPERGILLUS FUMIGATUS AND OPTIMIZATION OF CULTURAL CONDITIONS FOR AMYLASE PRODUCTION

P.V Ratnasri, B.K.M Lakshmi, K. Ambicadevi, K.P.J Hemalatha

Abstract: The soil samples were collected from different depths of paddy and sugarcane fields. The samples were primarily screened for isolation of amylase producing fungi. Among the isolated fungi, amylase producing isolates were identified by growing on starch agar media. The isolate (15F) which form the maximum zone of clearance on starch agar media by iodine was identified and it was subcultured on potato dextrose agar (PDA). The isolate (15F) was morphologically characterized by performing cotton blue staining and scanning electron microscopic observations under required magnifications. Molecular characterization of isolate (15F) was performed by ITS/5.8S rRNA and ß-tubulin gene sequence analysis and it was confirmed as Aspergillus fumigatus (MTCC Acc No 11399). Optimization of cultural conditions for maximum production of amylase was carried out by different cereal flours, incubation periods, temperatures, nitrogen sources and with different phosphate concentrations. Aspergillus fumigatus showed maximum amylase activity (230±0.7U/mg protein) when cultured in finger millet at 350C for 72hrs of incubation period.

Keywords: Amylase, Aspergillus fumigatus, cereal flour, submerged fermentation

DOI: https://doi.org/10.15623/ijret.2014.0302080