Screening of asporogenic mutants of phytase-producing Aspergillus niger CFR 335 strain

Gunashree, B. S. and Venkateswaran, G. (2009) Screening of asporogenic mutants of phytase-producing Aspergillus niger CFR 335 strain. Microbial Ecology in Health and Disease, 21. pp. 57-63.

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Abstract

Aspergillus niger is one of the fungi exploited industrially for the production of various metabolites including the enzyme phytase. Intensive sporulation is a serious crisis in using this fungus, hence, in the present study an attempt was made to obtain an asporulating strain.Materials and methods: A. niger CFR 335, a local phytase-producing isolate, was induced to physical mutation by ultraviolet (UV) radiation and chemical mutation using different concentrations of ethyl methane sulphonate (EMS) and N-methyl N?-nitro N-nitrosoguanidine (NTG).Results: UV exposure for 30 min, 10 mM EMS and 25 mg ml1 of NTG were found to be optimum for maximum killing effect of 26.3%, 95% and 80% of the spores, respectively. In this experiment, a stable auxotrophic mutant (ala) of A. niger CFR 335 with suppressed sporulation was obtained. The auxotrophic mutant M-1 (A. niger CFR 335 ala) showed an improved specific activity of 1.26 U mg1 as compared with the parent strain (0.85 U mg1).Conclusion: Sporulation was drastically reduced in the mutant M-1 without affecting phytase yield, whereas the production rate was proportional to the rate of sporulation in the parent strain (A. niger CFR 335).

Item Type:	Article
Uncontrolled Keywords:	asporulation, Aspergillus niger CFR 335, phytase, ethyl methane sulphonate, N- methyl N?-nitro N-nitrosoguanidine, ultraviolet radiation
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 04 Fungi
Divisions:	Food Microbiology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	01 Jul 2009 11:33
Last Modified:	23 May 2012 07:12
URI:	http://ir.cftri.res.in/id/eprint/9143

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