Purification and Characterization of Amyloglucosidase Produced by Aspergillus awamori NA21 under Solid State Fermentation using Tapioca Powder

Amyloglucosidase (α-1, 4 glucan glucohydrolase EC 3.2.1.3) hydrolyses amylaceous polysaccharides, removing successive glucose units in the β configuration from the non-reducing end of the chain. Amyloglucosidase is of considerable commercial importance to grain alcohol fermentation, food, textile and pharmaceutical industry. The aim of this study is to purify and characterize amyloglucosidase Produced by Aspergillus awamori NA21 under Solid State Fermentation (SSF) using Tapioca Powder. The enzyme was purified by sequential ammonium sulfate fractionation, DEAE-ion exchange chromatography and Sephadex G-100 column chromatography. Thermostability is increased by addition of thermo stabilizers, PEG 6000 and Ethylene glycol at 5 mM. The enzyme apparent molecular weight is determined by sodium dodecylsulfate polyacrylamide gel electrophoresis and gel filtration. The enzyme was purified approximately 68 fold with 54 percent recovery. The pH and temperature optima were 5.0 and 60°C, respectively. Enzyme was stable at temperature up to 40°C for 18 h and thermostability has increased to 24 h. The enzyme was stable at pH from 4.0 to 6.0. The enzyme was found to have apparent molecular weight of 61 kDa. The Michaelis Menten’s constant Km for soluble starch was 3.12 mg/ ml. The Vmax for soluble starch was 50.54 mg/ ml /min. The enzyme was activated by Ca 2+ but inhibited by Co 2+, Hg 2+, EDTA and Pb 2+ . The purified amyloglucosidase is stable in various organic solvents. This is the first report on purification of amyloglucosidase produced by Aspergillus awamori under SSF with tapioca powder as substrate.