| Polycyclic aromatic hydrocarbons(PAHs)are the hydrocarbons which have more than one fused benzene ring at the molecular level.They are widely spreading permanent organic pollutant which has high stability,high rate of biological enrichment,carcinogenic,teratogenic and mutagenesis effects,causing a great threat to ecological environment and human health.That's the reason why the effects of PAHs on water pollutions cannot be ignored.Activated sludge process is widely applied for the PAHs sewage treatment with a lot of features and advantages,such as more remarkable effects,lower costs and less polluted.For investigating the variation regularity of microbial community in activated sludge and its PAHs degradation mechanism while PAHs waste water treated with activated sludge process,we chose naphthalene and anthracene as the representative research objects,studying on the microorganism and the change rules of the related protein expressing in the waste water treated with activated sludge process.1.OTU analysis showed that: compared the OTU numbers of 90 days treatments with them of 30 days treatments,we found that the numbers of OTU were decreasing 34,12,150 and 114,respectively.The common OTU numbers of the four groups decreased by 156.It illustrates Anthracene and naphthalene and anthracene compound treatment on microbial community overall stress level greater;on the other hand,a total of OTU to the reduction in the number of shows that different treatment resulted in activated sludge microbial species constitute each other's differences increased,microbial community towards different directions differentiation.2.The dominant bacteria analysis showed that: the dominant bacteria of the four activated sludge groups were different from each other;During the treatment with naphthalene and anthracene compound,the values of the relative abundance of Burkholderiales in the community increased by 19.04% and 15.02% respectively after 90 days treatments than the values of 30 days treatments;during the treatment,the change of the relative abundance of Sphingomonadales was remarkable,the relative abundance of activated sludge treated with naphthalene,anthracene,naphthalene and anthracene compound was less than 1% after 30 days treatments,while they increased to 6.47%,3.69% and 10.03% after 90 days treatments.Burkholderiales and Sphingomonadales have been reported with polycyclic aromatic hydrocarbon degrading function and increased their relative abundance,suggesting that is adapted to naphthalene,anthracene stress results,but also improve the degradation ability of activated sludge of naphthalene and anthracene.3.Compared the protein extraction methods of oactivated sludge.The results showed that the samples extracted by SDS-phenol extraction,SDS-PAGE The number of the protein bands and the number of protein on the 2D-PAGE gel was higher.SDS-phenol extraction method is more suitable for total protein extraction from activated sludge.4.By SDS phenol extraction method and two-dimensional electrophoresis and matrix assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF-MS)combined with the technology of proteome analysis results showed that the four groups of sludge,only 90 days naphthalene treatment samples identified two known pathway of naphthalene degradation enzyme,the upstream NahA3 and NagB;at the same time,four groups of sludge for 30 days and 90 days in the sample treated with are identified to known biphenyl degradation pathway of seven enzymes in five,namely: BphA1,Bph B,Bph D,BphF and BphG;other identification to and a large number of sugar,fat,protein metabolism associated protein.Above all,this study was about the changes in microbial community structure and the degradation mechanism of PAHs in the activated sludge,it contributes to understand degradation microorganism of PAHs and its degradation pathway in activated sludge deeply.Thereby,it developed the potential of activated sludge in treating PAHs waste water better. |
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