INDUCTION OF HIGH PRODUCTIVE MUTANTS FOR LACTIC ACID IN RHIZOPUS ORYZAE AND THEIR IDENTIFICATION VIA DNA FINGERPRINTING

[54]

Talkhan, Fatma N.

ABSTRACT

        The fungus Rhizopus oryzae NRRL-395 was irradiated with UV light at different doses. Fifty induced stable mutants were isolated; eighteen of them selected according to their productivity as organic acids producers and tested for lactic acid production in comparison with their parental isolate and a local strain of this fungus. Three out of the tested mutants provide to overyield the original strain in concern to the production of lactic acid. Three others produced almost the same as their parent and the remainder twelve mutants produced it less than their parent, while the local strain did not produce this  acid.  DNA  fingerprinting  (RAPD), PCR-method was applied with five strains  including the parental strain, the high productive mutant no.3, the moderate productive mutant no.35, the local strain and the non productive mutant no.56 using three different random primers. The primer M13 is the best one giving a distinct DNA fingerprints by which the non lactic acid  producing  strains  (the  local  and  no. 56)  can  be  easily  distinguished from the producer strains by detect genetic polymorphism.