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- Title
Kinetics and Thermodynamic Properties of Glucose Oxidase Obtained from Aspergillus fumigatus ASF4.
- Authors
Iruoghene, Onosakponome; Linus, Ezugwu A.; Onyebuchi, Eze S. O.; Chiemeka, Chilaka F.
- Abstract
Heat instability is a major setback that prevents the broader use of glucose oxidase (GOx) in industries. This research explored the kinetic and thermodynamic parameters of Aspergillus fumigatus ASF4 GOx to determine its potential for biotechnological applications. Aspergillus fumigatus ASF4 GOx was purified 2.18-fold with a 6.25% yield after ammonium sulfate precipitation (60%), dialysis, ion-exchange chromatography, and gel filtration. The pH and temperature optima for GOx activity were 5.5 and 40°C, respectively. Metal ions, Ag2+ and Hg2+ had a remarkable inhibitory effect on GOx activity whereas Ca2+, Mg2+, and Mn2+ enhanced GOx activity. The maximum velocity (Vmax) and Michaelis constant (KM) were 2000 µmol/min, and 24 mM, respectively. The enzyme retained 85% and 90% of its initial activity at 40°C and 30°C, respectively after 120 min of incubation. At 50°C and 45°C, the enzyme retained more than 50% of its initial activity after 120 min of incubation. The k values at 37°C were the lowest (0.002) whereas that at 70°C was the highest (0.011). The Z-value was 0.3 and the activation energy (Ea) was 70.64 KJ/mol/K suggesting great sensitivity of GOx to temperature change. The D-value of Aspergillus fumigatus ASF4 GOx ranged between 115.5 to 208.4 min. The thermodynamic studies showed that glucose oxidation by Aspergillus fumigatus ASF4 GOx was reversible (ΔS<0), endothermic (ΔH>0), and non-spontaneous (ΔG>0) at all temperatures tested. The results on the optimum conditions for GOx activity and stability have shown that Aspergillus fumigatus ASF4 GOx can find application in the industrial production of gluconic acid.
- Subjects
GLUCOSE oxidase; ASPERGILLUS fumigatus; THERMODYNAMICS; ION exchange chromatography; RECOMBINANT DNA
- Publication
Tropical Journal of Natural Product Research, 2022, Vol 6, Issue 3, p438
- ISSN
2616-0684
- Publication type
Article
- DOI
10.26538/tjnpr/v6i3.22