Isolation and Identification of Glucose Oxidase Hyper Producing Strain of Aspergillus niger

Abstract

Aims: Glucose oxidase is an enzyme with large scale applications in various industries. It is also used in several diagnostic kits which makes it medically important as well. Our aim was to isolate indigenous glucose oxidase hyper producing strain of Aspergillus niger from different soil samples of Punjab, Pakistan. Study Design: An experimental study. Place and Duration of Study: Institute of Industrial Biotechnology, GC University, Lahore from March 2011 to July 2012. Methodology: Two hundred and seventy nine fungal strains were isolated from soil of different localities of Punjab. Isolates were screened for glucose oxidase production using submerged fermentation. Glucose oxidase hyper producer isolate was identified using morphological and molecular techniques i.e. 18S rDNA. DNA was isolated and amplified using PCR. Gene sequencing was done and homology analysis was studied. Rate of glucose oxidase production was also analysed. Results: Glucose oxidase hyper producing isolate was identified as A. niger A247 strain. This strain gave best reproducible results (145.22 ±0.034 U/g of cell mass) after 72 hrs of fermentation at 30ºC and at a medium pH of 7.2. Conclusion: Our results indicate the natural ability of A. niger to produce Glucose oxidase in large quantity instead of using genetic manipulation techniques.