| Autor: |
Zhao M; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China., Zheng G; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China., Kang X; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China., Zhang X; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China., Guo J; Northwest Institute of Eco-Environment and Resources, CAS, Donggang West Rd. 320, Lanzhou 730000, China., Wang S; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China., Chen Y; State Key Lab of Loess Science (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China., Xue L; School of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, No. 88, Anning West Road, Anning District, Lanzhou 730070, China. |
| Abstrakt: |
To explore the strong tolerance of bacteria to Hg pollution, aquatic Rheinheimera tangshanensis (RTS-4) was separated from industrial sewage, with a maximum Hg(II) tolerant concentration of 120 mg/L and a maximum Hg(II) removal rate of 86.72 ± 2.11%, in 48 h under optimum culture conditions. The Hg(II) bioremediation mechanisms of RTS-4 bacteria are as follows: (1) the reduction of Hg(II) through Hg reductase encoded by the mer operon; (2) the adsorption of Hg(II) through the production of extracellular polymeric substances (EPSs); and (3) the adsorption of Hg(II) using dead bacterial biomass (DBB). At low concentrations [Hg(II) ≤ 10 mg/L], RTS-4 bacteria employed Hg(II) reduction and DBB adsorption to remove Hg(II), and the removal percentages were 54.57 ± 0.36% and 45.43 ± 0.19% of the total removal efficiency, respectively. At moderate concentrations [10 mg/L < Hg(II) ≤ 50 mg/L], all three mechanisms listed above coexisted, with the percentages being 0.26 ± 0.01%, 81.70 ± 2.31%, and 18.04 ± 0.62% of the total removal rate, respectively. At high concentrations [Hg(II) > 50 mg/L], the bacteria primary employed EPS and DBB adsorption to remove Hg(II), where the percentages were 19.09 ± 0.04% and 80.91 ± 2.41% of the total removal rate, respectively. When all three mechanisms coexisted, the reduction of Hg(II) occurred within 8 h, the adsorption of Hg(II) by EPSs and DBB occurred within 8-20 h and after 20 h, respectively. This study provides an efficient and unused bacterium for the biological treatment of Hg pollution. |
