| Since 1950 s, chemical industry has developed rapidly following with The Third Industrial Revolution, Artificially Synthesized organics boomed day by day. These artificially synthesized organics make our life convenience, and on the other hand, they also bring many troubles. Persistent Organic Pollutants(POPs)are a sort of artificially Synthesized organics that are able to exist in environment persistently, transfer for long-distance, bio-accumulate through the food chain, have the serious poisonousness to people and environment. Due to the persistence, semi-volatility and long-distance transfer, bio-accumulation and serious poisonousness, human beings have already realized the serious impact of the POPs to the people's health and the economic development. Therefore, The United Nations Environment Programme(UNEP)convened a conference in Stockholm(the capital of Sweden)on the may 23 th 2001. In the conference, 90 countries including China signed the Stockholm Convention on Persistent Organic Pollutants, this Convention is aimed at prohibiting and restricting using 12 sorts of POPs.Polychlorinated Biphenyls(PCBs)are a sort of typical POPs, there are 209 isomers, because of the different amounts and positions of chlorins on benzene. PCBs were confirmed with teratogen?carcinogenicity and mutagenesis as other POPs, they are able to cause a serious of damages to people and animals. From 1977, the developed countries have stopped using and producing PCBs gradually, but due to the PCBs have a long half-life and hard to degrade under the natural conditions, the PCBs in environment is a hardly solved problem in the environment pollution field.The ability of microbial-phytoremediation is confirmed and applied to the degradation of POPs in environment. Microbial-phytoremediation is a development direction and a hot research field of environment bioremediation,it has a great application potential.In this study, we had isolated endophytic bacteria strains from Populus tomentosa, Salix matsudana f.pendula, Triarrherca sacchariflora and Brachypodium distachyon. From these endophytic bacteria strains, the strains which were able to degrade Aroclor 1242 were isolated through the POPs tolerance experiments using the POPs as the only carbon source experiments and the degradation experiments of Aroclor 1242. The research will help to understand the mechanism of microbial-phytoremediation on POPs, and enrich the PCBs degradation endophytic bacteria strains. The main results of this research are as follows:(1)37 endophytic bacteria strains were isolated, in which 35 strains were endophytic bacteria strains, and 2 were endophytic actinomyces strains.(2)24 strains could grow on different concentrations of POPs with culture media, showing the tolerance of the PCBs and Poly Brominated diphenyl ethers(PBDEs). Particularly, the domesticated strain CGL-1 had a great tolerance ability of POPs.(3)5 strains could use the POPs as the only carbon source to grow. The results of the morphological observation and the 16 Sr DNA sequence analysis preliminarily showed the strain 4?13and CGL-1 were Enterobacter sp., the strain SGL-1 was Klebsiella sp. and the strain CPY-4 was Bacillus licheniformis.(4)The optimum growth conditions of CGL-1 were 32? and p H 7. The optimized conditions for Aroclor 1242 degradation were 10% inoculum amount, 32? and p H 7. The gas chromatograms showed that strain CGL-1 had the degradation effects on each components of Aroclor 1242. Its total degrade rate of aroclor 1242 was 43.2% in 7 days.In conclusion, the endophytic bacteria strain CGL-1 was isolated from S. matsudana f.pendula tissue cultured materials, which was able to degrade the Aroclor 1242. It is Enterobacter sp. With the 10% inoculation amount of CGL-1, p H 7, 20mg/L Aroclor 1242 in 10 m L MSM, 32 ?, 200 r/min shaking culture for 7 days, its total degrade rate of aroclor1242 was 43.2%. It had the similar abilities to degrade the each components of the Aroclor 1242. |
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