Characterization Of Water Environmental Quality Situation And Preliminary Research On Poisonous Ferric Ions Reduction With Microorganisms

In recent years, along with the urban development, the ecological condition in the region of Dongting Lake is attracting more and more attention. We analyzed the bacterial diversity of the sewage sludge near the outfall of the nitrogenous fertilizer plant close to Dongting Lake. According to the analysis results of the bacterial community, we can find the bacterial diversity of SY sample is slightly far from the DZ sample, but there exists certain difference between the community structure of the two samples. The bacterial community structure analysis are identical with the multielement analysis, so it can be regarded as an indicator of evaluating the present water body pollution.Some certein microorganisms do have this capacity to couple with the reduction and detoxification of metal ions in the process of their growth, which promote the cycle of material exchange and energy flow.In this paper, based on the reducibility of Acidiphilium cryptum （A. cryptum）, we conducted a study on the dissimilatory reduction under different conditions with the A. cryptum DX1-1and Acidiphilium cryptum XTS isolated in our previous study. The results indicated that the reductive ability of Acidiphilium cryptum XTS was much better than A. cryptum DX1-1. The reduction rate of Fe（Ⅲ） was higher when glucose was selected as the sole carbon source. When adding the different initial concentration of Fe（Ⅲ）, with the increasing of initial Fe（Ⅲ） concentration, the ferrous iron concentration was enhanced, but the reduction rate of Fe（Ⅲ） was highest when the initial Fe（Ⅲ） concentration was0.5%. The reduction rate of Fe（Ⅲ） under aerobic and microanaerobic condition showed little difference, and the ferrous iron concentration was a little higher under aerobic condition. Although the dissimilatory reduction was tend to occur under anaerobic environment, it also would happen with the presence of oxygen. The PHB synthesis inhibitor a-ketoglutaric acid significantly improved the reduction rate of Fe（Ⅲ）, which increased from42.75%to73.01%.In addition, the protein ApcA （Acry₂099）, relating to the reduction properties of Acidiphilium spp., as well as the upstream promoter region was cloned and studied.