Partial characterization of proteases produced by three fungal isolates from the rhizosphere of wild yam Dioscorea wallichii

Among the twenty different fungal members isolated from the rhizosphere of wild yam, Dioscorea wallichii, three fungal isolates were found to be the best protease producers and identified as Aspergillus sp., Penicillium sp. and Trichoderma sp. The protease production studies of these three isolates were conducted up to 12 days. After nine days there was no significant increase in the enzyme production. Maximum protease activity was observed in the range of pH 6 and temperature 30C. Protease from all the three isolates was stable up to 2 h in dettol, tween 20, tween 80 and soap solution. Among the different immobilization techniques used agar block was the most effective. The molecular weight, zymogram analysis and destaining activity of the protease enzyme were also studied.