BARC/PUB/2015/0219

 
 

Microbial reduction of [Co(III)-EDTA](-) by Bacillus licheniformis SPB-2 strain isolated from a solar salt pan

 
     
 
Author(s)

Paraneeiswaran, A.; Shukla, S. K.; Prashanth, K.; Rao, T. S.
(W&SCD)

Source

Journal of Hazardous Materials, 2015. Vol. 283: pp. 582-590

ABSTRACT

Naturally stressed habitats are known to be repositories for novel microorganisms with potential bioremediation applications. In this study, we isolated a [Co(III)–EDTA]reducing bacterium Bacillus licheniformis SPB-2 from a solar salt pan that is exposed to constant cycles of hydration and desiccation in nature. [Co(III)–EDTA]generated during nuclear waste management process is difficult to remove from the waste due to its high stability and solubility. It is reduced form i.e. [Co(II)–EDTA]2−is less stable though it is toxic. This study showed that B. Licheniformis SPB-2 reduced 1 mM [Co(III)–EDTA]in 14 days when grown in a batch mode. However, subsequent cycles showed an increase in the reduction activity, which was observed up to four cycles. Interestingly, the present study also showed that [Co(III)–EDTA]−acted as an inducer for B. Licheniformis SPB-2 spore germination. Vegetative cells germinated from the spores were found to be involved in [Co(III)–EDTA]reduction. More detailed investigations showed that after [Co(III)–EDTA] reduction, i.e. [Co(II)–EDTA]2 −complex was removed by  B. Licheniformis SPB-2 from the bulk liquid by adsorption phenomenon. The bacterium showed a D10 value (radiation dose required to kill 90% cells) of ∼250 Gray (Gy), which signifies the potential use of B. Licheniformis SPB-2 for bioremediation of moderately active nuclear waste.

 
 
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