Microbial selenate detoxification linked to elemental sulfur oxidation: Independent and synergic pathways

JOURNAL OF HAZARDOUS MATERIALS

卷:422

Article

Li, Liuliu^1,2  Zhang, Baogang^1,2  Li, Lei^1,2  Borthwick, Alistair G. L.^3,4,5 

[1] China Univ Geosci Beijing, Sch Water Resources & Environm, Beijing 100083, Peoples R China

[2] China Univ Geosci Beijing, Minist Educ, Key Lab Groundwater Circulat & Evolut, Beijing 100083, Peoples R China

[3] St Edmund Hall,Queens Lane, Oxford OX1 4AR, England

[4] Univ Edinburgh, Sch Engn, Kings Bldg, Edinburgh EH9 3JL, Midlothian, Scotland

[5] Univ Plymouth, Sch Engn Comp & Math, Plymouth PL4 8AA, Devon, England

关键词: Elemental sulfur;    Selenate;    Microbial reduction;    Biodetoxification;   

DOI  :  10.1016/j.jhazmat.2021.126932

来源: Elsevier

【 摘 要 】

Elevated selenium levels in the environment, with soluble selenate [Se(VI)] as the common chemical species, pose a severe threat to human health. Anaerobic Se(VI) bioreduction is a promising approach for selenium detoxification, and various organic/inorganic electron donors have proved effective in supporting this bioprocess. Nevertheless, autotrophic Se(VI) bioreduction driven by solid inorganic electron donors is still not fully understood. This work is the first to employ elemental sulfur [S(0)] as electron donor to support Se(VI) bioreduction. A batch trial with mixed culture demonstrated the feasibility of this bioprocess, with Se(VI) removal efficiency of 92.4 +/- 0.7% at an initial Se(VI) concentration of 10 mg/L within 36 h. Continuous column tests showed that increased initial concentration, flow rate, and introduction of NO3--N depressed Se(VI) removal. Se (VI) was mainly bioreduced to solid elemental Se with trace selenite in the effluent, while S(0) was oxidized to SO42-. Enrichment of Thiobacillus, Desulfurivibrio, and Sulfuricurvum combined with upregulation of genes serA, tatC, and soxB indicated Se(VI) bioreduction was coupled to S(0) oxidation. Thiobacillus performed S(0) oxidation and Se(VI) reduction independently. Intermediate metabolites as volatile fatty acids, hydrogen and methane from S(0) oxidation were utilized by heterotrophic Se(VI) reducers for Se(VI) detoxification, indicative of microbial synergy.

【 授权许可】

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