Effect of tetrahydrofuran on enzyme activities in activated sludge

Tetrahydrofuran is an important solvent with wide usage in industry and laboratory research work. However, little information was known about the influence and fate of tetrahydrofuran (THF) in the environments. Several attempts have failed to enrich microorganisms in activated sludge to degrade THF. Effects of THF on the activities of dehydrogenase, protease, phosphatase, urease and catalase in activated sludge were investigated in this paper. The activated sludge was taken from the secondary sedimentation pool in the Sibao sewage treatment plant in Hangzhou China for observation of enzyme activities variation at the existence of tetrahydrofuran. The results obtained showed that tetrahydrofuran at over the range of selected concentrations could completely inhibit dehydrogenase activity during period of incubation, in the contrary, not to the protease activity, and strongly affected the phosphatase, urease and catalase activities which declined with increasing of tetrahydrofuran concentration. EC10, EC50, and EC90 of tetrahydrofuran on phosphatase, urease and catalase activities was calculated according to the equation obtained from regression model of dose–effect curve. Realizing the effect of THF on the enzymatic diversity in activated sludge can help us to understand the influence and fate of tetrahydrofuran in the environments, and help us to enrich THF-degrading pure isolates or activated sludge.