Arsenite is considered to be more toxic than arsenate (an average of 100 times). It can be oxidized to arsenate by chemical reaction or microbiological interactions. The aim of the present study was to investigate the arsenite-oxidizing microbes that exist in iron ore mine in India. We cultured 13 morphologically distinct bacterial strains, among which 6 strains could grow in high concentrations and shows the arsenite transforming abilities. Analysis of the amplified 16S rDNA gene sequences of the isolates revealed them to belong to alpha-, gamma- proteobacteria and firmicutes particularly in genera Paenibacillus, Pseudomonas, Ochrobactrum, Enterobacter and Bacillus. Further, qualitative silver nitrate screening assay and quantification by HPLC-ICP-MS analysis of these strains indicated the transformation of arsenite to arsenate. Moreover, the isolates were genetically analyzed for presence of arsenic arsenite transporter gene (arsB) that indicates the genetic ability of bacteria to tolerate the most toxic arsenic species.

中文翻译：

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废弃铁矿中微生物的砷氧化性能

砷被认为比砷具有更高的毒性（平均100倍）。可以通过化学反应或微生物相互作用将其氧化成砷。本研究的目的是调查印度铁矿中存在的砷氧化微生物。我们培养了13种形态上不同的细菌菌株，其中6株可以高浓度生长，并显示出亚砷酸盐转化能力。分离株的16S rDNA基因序列的扩增分析表明它们分别属于α-，γ-变形杆菌和硬毛病，特别是在Paenibacillus，Pseudomonas，Ochrobactrum，Enterobacter和Bacillus属中。此外，对这些菌株进行定性的硝酸银筛选测定和通过HPLC-ICP-MS分析的定量表明了亚砷酸盐向砷酸盐的转化。此外，对分离物进行了遗传分析，分析其是否存在砷砷转运蛋白基因（arsB），这表明细菌具有耐受最高毒性砷物种的遗传能力。