The Toxicology Of Triclocarban And Isolation And Identification Of The Triclocarban-degrading Bacterium

To be directed against the current extensive use and distribution of the TCC in the environment, the influence of TCC on the amount of nitrifying bacteria, denitrifying bacteria, ammonifying bacteria in soil and some growth, physiological and biochemical indexes of barley were investigated. It provided an experimental basis for the harm of TCC on the microbes and plants in the environment. We also isolated and selected strains which can degrade TCC effectively from activated sludge. It provided reference and resources for the removal of environmental pollution of TCC and the development of Environmental Microbiology. The conclusions of this study as follows:1. Treated with different TCC concentrations of 0,10,20,40 and 60mg/kg, the amount of nitrifying bacteria, denitrifying bacteria and ammonifying bacteria have taken place significant changes, reflecting a different inhibition-activation effect. In the 72d trial period, the effect of TCC on the number of nitrifying bacteria showed effects, and with the TCC application concentration, the activation effects gradually increased; The number of denitrifying bacteria showed the activation at first, then showed the inhibition; The number of ammonifying bacteria showed inhibition effect obviously.2. In this study, barley seedlings were treated with different TCC concentrations of 0,10,50,100,200 and 300 mg/L(mg/kg) as materials. Changes in maximum root length, plant height and physiological indices in aerial parts and underground parts of barley seedlings caused by TCC treatment were investigated using hydroponic and soil culture.In the experiment of seedling growth of barley in the TCC target, the hydroponic culture experiments showed that, with the increasing of TCC in culture medium, the maximum root length and plant height differences were highly significant compared with the control. The maximum root length decreased 39%,65%,81%,81%,87% and plant height decreased 18%,35%, 71%,80%,88% compared with the control. Soil culture experiment showed that, with the TCC concentration of 50,100,200,300mg/kg in soil, the difference of maximum root length reached a significant level and decreased 18%,32%,32%,41% respectively compared with the control. With the TCC concentration of 300mg/kg in soil, plant height differences were significant, increased 4.5% compared with the control.In the experiment of physiological and biochemical of barley in the TCC target, the hydroponic culture experiments showed that, with the increasing of TCC in culture medium, SOD, POD activity, H2O2, MDA content increased, CAT activity decreased in the aerial parts of barley, and POD activity, H2O2 content increased, SOD activity, MDA content decreased firstly and then increased, CAT activity increased firstly and then decreased in the underground parts of barley. The soil culture experiment showed that, with the increasing of TCC in soil, CAT activity decreased, SOD, POD activity, H2O2, MDA content increased firstly and then decreased in the aerial parts of barley, and POD, CAT activity, H2O2, MDA content decreased, SOD activity did not change significantly in the underground parts of barley. The change of physiological indices was quite prominent in all signs compared with the control.3. Nine strains of TCC degrading strains were isolated from activated sludge of sewage treatment plant, which had a certain degradation ability against TCC. The degradation capability test showed that JC02 had the strongest degradation ability in the degrading medium, which were treated with different TCC concentrations of 200～1000mg/L. And the degradation rate were 12.2%,18.6%,12.9%,13.2% and 10.2% respectively, so JC02 has good potential for development and application. Based on the observation of morphological characteristics, the analysis of physiological and biochemical characteristics and identification of molecular biology to determine the JC02 as Bacillus cereusstrain.