PJB-2017-336
Kinetic and thermodynamic analysis of purified pectinases produced from nitrous acid mutant derivative of Aspergillus niger (H-97)
Nauman Jamil Khan, Ikram-Ul-Haq, Ali Nawaz, Asad Ur Rehman and Hamid Mukhtar
Abstract
The Aspergillus niger mutant strain H-97 was used for pectinase production (40.31±0.07 U/ml/min) having specific activity of 12.12 ± 0.01 U/mg. Fermentation was carried out using 5 liters of fermentation medium in 7.5 liter stirred fermenter under controlled condition of temperature (30°C), pH (07), agitation (200 rpm), aeration (1vvm) for an incubation time of 48 h using 1% vegetative inoculum. Purification of enzyme resulted in 44.20% yield with enhancement of specific activity (75.18±0.04 U/mg) by ammonium sulfate precipitation and ion exchange chromatography. Kinetic characterization of enzyme revealed pectin as highly specific substrate for enzyme with Km value of 2.30 mg/ml. Thermodynamic evaluation of enzyme resulted in activation energy (Ea) as -28.95 KJ/mol and enthalpy of activation (ΔH) as -26.73 KJ/mol.
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