In Situ Detection Of Anammox Bacteria In Freshwater Sediments And Study On Their Cultivation

Anaerobic ammonium oxidation (anammox) is a newly discovered process in nitrogen cycle in aquatic systems, and it plays a significant role in the conversion of nitrogen. However, the research on the ecological characteristics of anammox bacteria and the application of anammox process in bioaugamentation of environmental pollution is still at the beginning. Based on the previous studies, the research in this paper was carried out, mainly including two parts as follows:(1) Anammox bacteria and aerobic ammonia oxidizers were detected in situ in 6 sediment samples taken from Jiangsu Province. Molecular techniques, such as FISH, PCR, DNA cloning and sequencing etc. were used for this purpose.(2) The continuous cultivation of anammox bacteria from sediment samples were studied, which provides experimental basis for the bioaugamentation of eutrophicated sediment applying anammox process.Through the above studies, the following conlusions were gained:(1) Anammox bacterium is present in sample XYR2 taken from Xinyi River. Phylogenetic analysis showed that this newly discovered anammox bacterium is affiliated to Brocadia.(2) Some of the clones of sample XYR1 and XYR2 form a new branch of planctomycetes. But the functions of these bacteria are unknown.(3) There are at least two species of AOB belonging to Nitrosomonas in sample XYR2. One of them is affiliated with Nitrosomonas marina (cluster 6b); while another is affiliated with Nitrosomonas cluster 5. This result indicates that AOB and anammox bacteria can also coexist in natural environment besides bioreactors.(4) Conclusions still can't be made from the continuous cultivation of anammox bacteria because of limitation of time. But it is the basis for further study.