ISSN : 0975-9492


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Title : Isolation of a hyperamylolytic mutant strain of Rhizopus oryzae PR7 by Classical Mutagenesis
Authors : Barnita Ghosh, Rina Rani Ray
Keywords : Rhizopus oryzae, Isoamylase, MNNG, classical mutagenesis
Issue Date : March 2013
Abstract :
Purpose: In order to increase the ability to produce isoamylase, the isoamylolytic wild strain of Rhizopus oryzae PR 7, MTCC 9642 was subjected to chemical mutagenesis by N-methyl-N'-nitro-nitroso guanidine (MNNG) . Methods: Among the surviving strains, those strains showing improved amylolytic activity both by in situ assay on iodine stained starch agar plate and in vitro assay by reducing sugar measurement were selected and subcultured subsequently for three generations. Results: Strain named K1 was found to be the best amylase synthesizing mutant strain. Glycogen (0.5%) was found to be the best inducer followed by pure and indigenous starch types. The selected mutant strain showed maximum production on 96th hour of cultivation and a persistent enzyme production till 120th hour. At this hour glycogen induced production by K1 strain showed a 5.59 times increase in enzyme production than that of the wild strain. Preliminary characterization showed an achievement of increased pH and thermo stability by the enzyme of the mutant strain. Conclusion: Hence the mutant strain K1 could be used for commercial production of isoamylase using cheap or waste sources of starchy materials.
Page(s) : 36-41
ISSN : 0975-9492
Source : Vol. 4, No.3