With the development of modern industry, the application of tellurium is increasing. The pollution of tellurite become more and more serious, and the tellurium compounds can be found in water and soils around most industrial wastewater discharge position. The tellurite oxyanions is the most water soluble and toxic to both eukaryotic and prokaryotic organisms. Although tellurium compounds can not be degradated, microorganism can transfer physical and chemical property and change the mobility. In this paper, reduction of tellurite to tellurium by Pseudomonas. sp MBR were discribled.
The tellurite was reduced in the liquid medium or solid plates to dark crystal tellurium by Pseudomonas. sp MBR, and the reduction process need directly contacted between bacteria and tellurite oxyanions. The toxicity of tellurite do great damages to cells lead to lysis, and the crystal tellurium assembled in the cytoplasm.
The toxicity of tellurite inhibit the growth of Pseudomonas. sp MBR. During batch culture, the least biomass harvested from the medium added the most tellurite sodium. The tellurite reduced and the biomass have a positive correlation, and increased biomass favored reduction.
Nutrients have different influences to tellurite reduction. The tellurite reduction is the highest with the citrate as the carbon sources. Nitrogen sources nitrate or ammonia have no difference in tellurite reduction. Increased nitrate and phosphate decreased tellurite reduction, and no differences were found when sulfate increased.
Plasmids were not found in the Pseudomonas. sp MBR, GSH and RSH have no effect on the tellurite reduction. Tellurite reduction enzyme were not detected
The lab-scale of CSTR is conducted with the glucose as the carbon source in the medium added tellurite sodium. The result show that: influent concentration of 10mg/L, HRT of 12h, effluent tellurite is lower than 1mg/L. Influent concentration of 20mg/L, HRT and carbon concentration doubled, the effluent concentration of 3mg/L or so.
Toxic tellurite can be wipped off from environment through reduction to crystal tellurium located in catoplasm by Pseudomonas. sp MBR, and the bacteria have a high resistence level to tellurite sodium. High concentration nitrate, phosphate, sulfate have little influence on reduction , and many carbon sources can be as electron donor. Bioreactor experiment data proved that low tellurite level easily be treated. All in all, it has an advantage in application using Pseudomonas. sp MBR to decrease tellurite pollution. At the same time, Pseudomonas. sp MBR provide a new object for reduction mechanism due to its special character.