Exploitation of wild and mutant strains of Aspergillus niger (MBL-33) for enhanced lipolytic potential

The present investigation describes the production of lipases (triglycerol acyl-hydrolases; e.c. 3.1.1.3) by using nitrous acid,a mutagen affecting non-replicating dna,to enhance the enzyme potential of the strain using submerged fermentation technique. a native fungal strain of aspergillus niger (mbl-33) was subjected to mutagenic treatment @ the dose rate of 0.1m nitrous acid. time interval of mutagenic treatment ranged from 30 to 180 minutes. a potent mutant of a. niger (mbl-33) with an increased activity of 423% over the wild strain was obtained after screening out of fifty mutants. various basal medium was tested in order achieve ideal combination of carbon and nitrogen sources for enhanced enzyme production. medium m-7 supported highest output of enzyme by both wild and mutant strains. the optimum conditions for the best lipases activity were attained by using 1.0 ml inoculum level at 30oc after 32 h at ph of 9. sucrose & peptone were the best additional carbon & nitrogen source @ 1% concentration respectively. calcium (ca2+) proved the best metal ion as it supports the maximum lipases production by wild (24.52±0.37a u/ml) and mutant (98.21±0.24a u/ml) strain at the concentration of 1mm. © 2015,pakistan botanical society. all rights reserved.