Journal of Environmental Biology

Development of new medium composition for enhanced

production of L-asparaginase by Aspergillus flavus

Krishna Raju Patro, Uday Chand Basak, Ajay Kumar Mohapatra and Nibha Gupta*

Regional Plant Resource Centre, Bhubaneswar- 751 015, India

*Corresponding Author E-mail: nguc2003@yahoo.co.in

Publication Data

Paper received:

10 September 2012

Revised received:

01 March 2013

Re-revised received:

10 April 2013

Accepted:

03 June 2013

Abstract

The present study on L-asparaginase from Aspergillus flavus was aimed to optimize the culture and nutritional conditions in order to obtain enhanced enzyme production under batch culture. Aspergillus flavus was grown in different combination of carbon and nitrogen source and L-asparaginase from its biomass was estimated. Finally, L- asparaginase extracted from cell biomass was purified through gel filtration and ion exchange chromatography and characterized for its purity, molecular weight, K_m value thermal tolerance and pH requirement. The fungal species preferred starch and sorbitol as carbon and L- asparagine and L- glutamine as nitrogen source. Addition of ionic compounds or basal nitrogen sources did not help in enhancing enzyme activity. Gel filtration and ion exchange chromatography produced pure enzyme which was later confirmed through PAGE with molecular weight 100.0 kDa. L ? asparaginase from Aspergillus flavus preferred L-asparagine as substrate, 7 pH , thermally stable upto 50?C and showed 0.806x10-3 M K_m. L ?asparaginase from bacterial origin sometimes cause severe allergic reactions. Search of new sources especially of fungal origin may be useful in development of potential drug. The media composition given in the present study can be further used in continuous fermentation for large scale production of L ? asparaginase. 

Key words

Aspergillus flavus, L-asparaginase, Microbial enzymes

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