Arsenic Research Laboratory, Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741235, West Bengal, India.
Sci Total Environ. 2013 Oct 1;463-464:1006-14. doi: 10.1016/j.scitotenv.2013.06.068. Epub 2013 Jul 20.
As biological agents represent an affordable alternative to costly metal decontamination technologies, we isolated arsenic (As) oxidising bacteria from the As-contaminated soils of West Bengal, India. These strains were closely related to various species of Bacillus and Geobacillus based on their 16S rRNA gene sequences. They were found to be hyper-resistant to both As(V) (167-400 mM) and As(III) (16-47 mM). Elevated rates of As(III) oxidation (278-1250 μM h(-1)) and arsenite oxidase activity (2.1-12.5 nM min(-1) mg(-1) protein) were observed in these isolates. Screening identified four strains as superior As-oxidisers. Among them, AMO-10 completely (100%) oxidised 30 mM of As(III) within 24 h. The presence of the aoxB gene was confirmed in the screened isolates. Phylogenetic tree construction based on the aoxB sequence revealed that two strains, AGO-S5 and AGH-02, clustered with Achromobacter and Variovorax, whereas the other two (AMO-10 and ADP-25) remained unclustered. The increased rate of As(III) oxidation by these native strains might be exploited for the remediation of As in contaminated environments. Notably, this study presents the first correlation regarding the presence of the aoxB gene and As(III) oxidation ability in Geobacillus stearothermophilus.
由于生物制剂是一种比昂贵的金属去污技术更经济实惠的替代方案，我们从印度西孟加拉邦受砷污染的土壤中分离出了砷氧化细菌。这些菌株的 16S rRNA 基因序列与各种芽孢杆菌和地芽孢杆菌密切相关。它们对砷（V）（167-400 mM）和砷（III）（16-47 mM）均具有高度抗性。这些分离株的砷（III）氧化速率（278-1250 μM h(-1)）和亚砷酸盐氧化酶活性（2.1-12.5 nM min(-1) mg(-1) 蛋白）均较高。筛选出了四株具有优异砷氧化能力的菌株。其中，AMO-10 在 24 小时内可完全（100%）氧化 30 mM 的砷（III）。在所筛选的分离株中均确认存在 aoxB 基因。基于 aoxB 序列构建的系统发育树显示，两株菌株AGO-S5 和 AGH-02 与不动杆菌属和鞘氨醇单胞菌属聚为一簇，而另外两株（AMO-10 和 ADP-25）则未聚类。这些本地菌株提高的砷（III）氧化速率可用于受污染环境中砷的修复。值得注意的是，本研究首次证明了地芽孢杆菌中 aoxB 基因的存在与砷（III）氧化能力之间存在相关性。
