Investigation of protease enzyme activities of nematode-trapping fungi species (Arthrobotrys spp. and Drechslerella spp.) isolated from soil samples of the greenhouse tomato growing area of the West Mediterranean Region

In this study, protease enzyme activities of nematode trap fungus species isolates, Arthrobotrys conoides, A. oligospora, A. thaumasia, Drechslerella brochopaga, and D. dactyloides isolated from soils of tomato-grown greenhouses from the Western Mediterranean Region were investigated. Both semiquantitative and quantitative protease enzyme activities of nematode trap fungus isolates were performed. According to the semiquantitative analysis results, it was determined that 1 isolate had weak, 2 isolates had strong, and 9 isolates of the 12 tested nematode trap isolates had very strong protease enzyme activity. Quantitative enzyme activity studies were carried out with crude enzyme extracts obtained from nematode trap fungus isolates. The all isolates were evaluated according to their quantitative protease enzyme activities for azocasein substrate, and the highest activity was found in the B-G8-1 isolate of Arthrobotrys thaumasia species. Using azocasein as a substrate, enzyme activities of the crude protease enzyme obtained for each isolate were measured at the pH values 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0 and at temperature values 15, 20, 25, 30, 35, 40, 45, and 50°C; the optimum pH and temperature values were determined. The protease enzyme activities of each isolate were measured towards azocasein substrate at different concentrations at the experimentally determined optimum pH and temperature values for the protease enzyme, and KM and Vmax values were determined by using the Lineweaver-Burk graph. SDS-PAGE was applied to the crude extract containing protease enzyme obtained from each nematode trap fungus isolate.