PECTINASE PRODUCTION BY UV‐2DG RESISTANT MUTANT OF Aspergillus niger WITH A CATABOLITE REPRESSION RESISTANCE ACTIVITY

Abstract

Strain improvement of microfungi for hyper production of industrial enzymes is important in the biodegradation of agrowastes to valuable product. Wild strain of Aspergillus niger previously isolated from agrowastes in Lagos Nigeria, was screened for pectinase production in various agro wastes. This strain was further subjected to UV‐mutagenesis; through the use of a selective culture medium containing 2 deoxy D glucose (2dg) it was possible to isolate hyper productive mutant strains (resistant to 2dg). Pectinase production by the mutant was monitored for 72h in both SSF and SmF and the effect of catabolite repression was also studied using glucose and sucrose. The wild strain of Aspergillus niger produced high level of pectinase in all the agrowaste studied with the highest pectinase activity in wheat bran medium (348.54 IU/mg protein).Three 2dg UV mutant were isolated, the best 2dg UV mutants (2dg UV A.n 2) showed 465% and 230% higher pectinase activity than the parent strain in SSF and SmF respectively. This mutant is also noted to be resistance to catabolite repression in both glucose and sucrose containing medium. The result indicated that UV mutation and 2 dg were effective mutagenic and selectant for strain improvement of Aspergillus niger for enhanced pectinase production.