Isolation and characterization of a Lysinibacillus strain B1-CDA showing potential for bioremediation of arsenics from contaminated water

Abstract

The main objective of this study was to identify and isolate arsenic resistant bacteria that can be used for removing arsenic from the contaminated environment. Here we report a soil borne bacterium, B1-CDA that can serve this purpose. B1-CDA was isolated from the soil of a cultivated land in Chuadanga district located in the southwest region of Bangladesh. The morphological, biochemical and 16S rRNA analysis suggested that the isolate belongs to Lysinibacillus sphaericus. The minimum inhibitory concentration (MIC) value of the isolate is 500 mM (As) as arsenate. TOF-SIMS and ICP-MS analysis confirmed intracellular accumulation and removal of arsenics. Arsenic accumulation in cells amounted to 5.0 mg g⁻¹ of the cells dry biomass and thus reduced the arsenic concentration in the contaminated liquid medium by as much as 50%. These results indicate that B1-CDA has the potential for remediation of arsenic from the contaminated water. We believe the benefits of implementing this bacterium to efficiently reduce arsenic exposure will not only help to remove one aspect of human arsenic poisoning but will also benefit livestock and native animal species. Therefore, the outcome of this research will be highly significant for people in the affected area and also for human populations in other countries that have credible health concerns as a consequence of arsenic-contaminated water.

Keywords:

• Pollution
• toxic metals
• arsenics
• bioremediation
• bacteria
• bioaccumulation

Acknowledgment

We acknowledge the Swedish South Asian Studies Network (SASNET) in Lund for delivering us information on South Asian research.

Additional information

Funding

This research has been funded mainly by the Swedish International Development Cooperation Agency (SIDA, grant no. AKT-2010-018) and partly by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS, grant no. 229-2007-217). A small grant from the Nilsson-Ehle (The Royal Physiographic Society in Lund) foundation in Sweden is also acknowledged.