Chemical Mutagenesis of Penicillium italicum for the Development of Catabolite Insensitive Mutants

Abstract

The objective of this study was to enhance mannanase production through chemical mutagenesis and to develop catabolite insensitive mutants. Mutants were generated by incubating spore suspension of Penicillium italicum with varying concentrations of Ethyl Methane Sulfonate (EMS). Wild type and mutants were screened for mannanase production in basal media supplemented with Locust Bean Gum (LBG) as an inducer. Mannanase activity was determined by dinitrosalicylic acid method, while protein content was determined by Lowry method. Approximately 46% of the mutants generated showed higher mannanase activity in comparison with the wild type, while repression of enzyme biosynthesis was observed in others. The isolated mutants were screened for catabolite activation studies in the presence of different mannose concentrations (0.1, 0.5 and 1% w/v) as a carbon source. The supplementation of 0.1% (w/v) mannose in the fermentation media caused enhancement of mannanase synthesis in approximately 54% of the mutants. The supplementation of 0.5 and 1% (w/v) mannose in the fermentation media caused improvement of mannanase biosynthesis in 100% and approximately 62% of the mutants, respectively. The results indicated that EMS might be an effective mutagenic agent for the development of catabolite insensitive mutants.