title: Kinetic characterization of glucose aerodehydrogenase from Aspergillus niger EMS-150-F after optimizing the dose of mutagen for enhanced production of enzyme.
abstract: In the present study enhanced production of glucose aerodehydrogenase from Aspergillus niger has been achieved after optimizing the dose of chemical mutagen ethyl methane sulfonate (EMS) that has not been reported earlier. Different doses of mutagen were applied and a strain was developed basing upon the best production. The selected strain Aspergillus niger EMS-150-F was optimized for nutrient requirements in order to produce enzyme through fermentation and the results showed the best yield at 2% corn steep liquor (CSL), 36 hours fermentation time, pH 5, 30 °C temperature, 0.3% KH2PO4, 0.3% urea and 0.06% CaCO3. The enzyme was then purified and resulted in 57.88 fold purification with 52.12% recovery. On kinetic characterization, the enzyme showed optimum activity at pH 6 and temperature 30 °C. The Michaelis-Menton constants (K(m), Vmax, Kcat and Kcat/K(m)) were 20 mM, 45.87 U mL(-1), 1118.81 s(-1) and 55.94 s(-1) mM(-1), respectively. The enzyme was found to be thermally stable and the enthalpy and free energy showed an increase with increase in temperature and ΔS* was highly negative proving the enzyme from A. niger EMS-150-F resistant to temperature and showing a very little disorderliness.
authors.affiliation: Enzyme Biotechnology Laboratory, Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad, Pakistan.
authors.forename: Huma
authors.initials: H
authors.lastname: Umbreen
authors.affiliation: Enzyme Biotechnology Laboratory, Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad, Pakistan.
authors.forename: Muhammad Anjum
authors.initials: MA
authors.lastname: Zia
authors.affiliation: Enzyme Biotechnology Laboratory, Department of Chemistry and Biochemistry, University of Agriculture, Faisalabad, Pakistan.
authors.forename: Samreen
authors.initials: S
authors.lastname: Rasul
mesh_terms: D001234:Aspergillus niger / Q000187:drug effects / Q000201:enzymology*; D003470:Culture Media / Q000737:chemistry; D004795:Enzyme Stability; D005947:Glucose / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D060847:Metabolic Engineering / Q000379:methods*; D016296:Mutagenesis; D009153:Mutagens / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
chemical_list: D003470:Culture Media; D009153:Mutagens; D010088:Oxidoreductases; D005947:Glucose
keywords: glucose aerodehydogenase; mutagenesis; production; purification; thermal stability