The role of some mineral elements , carbon and nitrogen sources in the activity of protease enzyme produced from a local isolate of Aspergillusniger*


Series of lab.experiments were conducted in the postgraduate lab.Biol.Dept.,College of Education for Pure Science from November,2012till December,2013.Local isolated of Aspergillus niger, was obtained,isolated,diagnosed and then a qualitative test was carried out to determineits efficiency in the proteolysis of protein.The diameter of the clear zone arround the fungal colonies was more than15mm,The protease activity was 18.97 U/ml with0.460 mg/ml protein.Mineral nutrients and different sources of carbon and nitrogen were used to test their ability in the fungal growth and secretion of protease enzyme.Using MgSO4 and KH2PO4 together activated the production of protease enzyme gving 28.82 U/mg protein compared to the control which gave 22.39 U/mg protein. Resulls revealed that, glucose was better source for protease enzyme production compared with ther carbohydrates sources used. Maxemum enzyme activity of protease reauled 35.72 U/mg protein,whereas, the minimu enzyme activity was found in the presence of Lactose. The best conc.of glucose for protease enzyme production was 1.5% where the enzymatic activity was 40.42 U/mg protein. Gazaen was the most efficient N source in enzyme production compared to other nitrogen sources used, wher the enzymatic activity of protease reached 43.89 U/mg protein. Mean while, the lowest enzyme activity of protease was found with the presence of ammonium salphalt giving 7.55 U/mg protein. Maxemum enzymatic activity was recorded when Gazaen was used at 1% reaching 47,51 protein of protease enzyme. Whereas, qualitative activity gradually decreased with increasing N source used in this study giving 10.53U/mg protein at 2% Gazaen.