Molecular Biogeochemistry Laboratory, Yanbian University of Science and Technology, 3458 Chao Yang Street, Yianji, Jinlin Province 133-000, China.
J Hazard Mater. 2011 Oct 15;193:233-42. doi: 10.1016/j.jhazmat.2011.07.055. Epub 2011 Aug 4.
The potential biogeochemical redox activity of arsenic was investigated by examining bacterial arsenic (As) redox genes such as aox, ars, and arr in arsenic-contaminated abandoned mine area and adjacent coastal sediments. Consistent with aerobic sediment and water samples from the mine through coastal areas, bacterial genes involing arsenic(V) (arsenate, AsO(4)(3-)) reduction such as arsC and arrA were identified only in a few samples, where's bacterial aoxB gene encoding arsenite oxidase which is a central role in arsenic(III) (AsO(2)(-)) oxidation of aox operon. This study suggests that evaluation of arsenite-oxidizing bacteria including aox genotype may lead to a better understanding of molecular geomicrobiology in arsenic biogeochemistry, which can be applied to the bioremediation of arsenic contaminated mines along the coast of Gwangyang Bay. In this study, high concentrations of arsenic were observed in the mines and Gwangyang Bay and it was speculated that As(III)-oxidizing bacteria isolated from those highly arsenic-contaminated areas contributed the biogeochemical cycling of arsenic by transforming arsenic species and resulting in change of mobility, though further in situ biogeochemical and/or microbial ecological investigations are needed for confirming the phenomena in natural environment. Acinetobacter junni and Marinobacter sp. which were isolated in the contaminated area contained the aox genes and were able to oxidize As(III) to As(V), which is a more soluble form in oxic aqueous environments and apt to migrate from the mine to the coast. This might suggest a potential of a significant redox role of aox genes of arsenic-oxidizing bacteria in biogeochemical cycle of arsenic.
本研究通过检测砷污染废弃矿区及其毗邻海岸沉积物中细菌砷（As）氧化还原基因（如 aox、ars 和 arr），研究了砷的潜在生物地球化学氧化还原活性。与矿区到沿海有氧沉积物和水样一致，仅在少数样品中鉴定到参与砷（V）（砷酸盐，AsO4(3-)）还原的细菌基因arsC 和 arrA，而细菌 aoxB 基因编码亚砷酸盐氧化酶，在 aox 操纵子中起砷（III）（AsO2(-)）氧化的核心作用。本研究表明，评估包括 aox 基因型在内的亚砷酸盐氧化细菌，可能有助于更好地理解砷生物地球化学中的分子地球微生物学，这可应用于沿光阳湾海岸砷污染矿山的生物修复。在本研究中，矿区和光阳湾的砷浓度很高，据推测，从这些高砷污染地区分离出的 As(III)-氧化细菌通过转化砷物种并导致迁移性变化，从而促进砷的生物地球化学循环，尽管需要进一步进行原位生物地球化学和/或微生物生态调查，以确认自然环境中的这些现象。在污染区分离到的不动杆菌属（Acinetobacter junni）和海洋杆菌属（Marinobacter sp.）含有 aox 基因，能够将 As(III)氧化为 As(V)，As(V)在含氧水相环境中溶解度更高，且易从矿山迁移到海岸。这可能表明，砷氧化细菌的 aox 基因在砷的生物地球化学循环中具有重要的氧化还原作用。
