Comparison On Fermentation And Properties Of Protease And Esterase Of Trichosporon Fermentans

Microbial protease and esterase are important industrial enzymes, they have been applied in the field of food,chemical, medicine and environment. In this paper, the location of the protease and esterase by Trichosporon fermentans; the conditions of crushing cell by ultrasonic; the enzymatic properties and fermentation conditions of protease and esterase and the mutual influence between protease and esterase in the process of fermentation and catalytic reaction were analysed. The results are as following.The protease produced by Trichosporon fermentans is endoenzyme and the esterase is intracellular enzyme; conditions of crushing Trichosporon fermentans by ultrasonic were that:output power550W, total irradiation time13min, duration of irradiation each time7s (with a5s interval), the amount of phosphate buffer per gram cells20mL, under which the activity of protease extracted could reached393.78U·g-1.The seeds liquid were used to fermentation, which were obtained from the seed culture medium with different glucose concentrations.When glucose concentration was40g/L, the bacterial productivity will be up to0.432g/100mL. When glucose concentration was80g/L, the activity of protease and esterase produced will be the hightest. Tprotease activity will be up to308.8U/g at60fermentation time; the biggest esterase activity will be up to539.3U/g at70fermentation time.The optimum reaction pH and temperature of protease and esterase are found to be7.0、53℃andpH7.0、40℃.5mmol/L Ca2+、Mn2+, Pb2+increased the activity of protease and esterase.Ca2+increased the protease activity to187%, Mn2+、Fe3+increased the activity of the esterase.Mn2+increased the esterase activity to106.9%.The activity of proteases and esterases was decreased after adding5mmol/L Mg2+、Cu2+、Zn2+.The protease activity was only59.4%of the activity of original enzyme solution after adding Zn2+. The proteases activity did not change after adding Tween80,Tween40,SDS and CTAB.0.01%Tween100increased the protease activity to124%. The activity of esterases was decreased after adding Tween40, Tween100,0.01%SDS and CTAB made esterase completely inactivation.