Arsenite biotransformation and bioaccumulation by Klebsiella pneumoniae strain SSSW7 possessing arsenite oxidase (aioA) gene
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Arsenite oxidizing Klebsiella pneumoniae strain SSSW7 isolated from shipyard waste Goa, India showed a minimum inhibitory concentration of 21 mM in mineral salts medium. The strain possessed a small supercoiled plasmid and PCR amplification of arsenite oxidase gene (aioA) was observed on plasmid as well as chromosomal DNA. It was confirmed that arsenite oxidase enzyme was a periplasmic protein with a 47% increase in arsenite oxidase activity at 1 mM sodium arsenite. Scanning electron microscopy coupled with electron dispersive X-ray spectroscopic (SEM–EDS) analysis of 15 mM arsenite exposed cells revealed long chains of cells with no surface adsorption of arsenic. Transmission electron microscopy combined with electron dispersive X-ray spectroscopic (TEM-EDS) analysis demonstrated plasma membrane disruption, cytoplasmic condensation and periplasmic accumulation of arsenic. The bacterial strain oxidized 10 mM of highly toxic arsenite to less toxic arsenate after 24 h of incubation. Fourier transformed infrared (FTIR) spectroscopy confirmed the interaction of arsenite with functional groups present on the bacterial cell surface. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of 5 mM arsenite exposed cells demonstrated over-expression of 87 kDa and 14 kDa proteins of two subunits aioA and aioB of heterodimer arsenite oxidase enzyme as compared to control cells. Therefore, this bacterial strain might be employed as a potential candidate for bioremediation of arsenite contaminated environmental sites.
KeywordsArsenite AioA gene Bioremediation Biotransformation
SM is grateful to University Grants Commission, New Delhi for financial support as Maulana Azad National Fellowship (SRF). The authors are thankful to Areef Sardar from CSIR- National Institute of Oceanography, Goa for EDX analysis; AIRF, Jawaharlal Nehru University, New Delhi for TEM–EDX analysis; B. R. Srinivasan, Head, Department of Chemistry and Rahul Kerkar from Department of Chemistry, Goa University for FTIR analysis. SM is also thankful to Sandeep Garg, Head, Department of Microbiology, Goa University for providing laboratory facilities.
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Conflict of interest
The authors declare that there is no conflict of interest.
- Arsene-Ploetze F, Koechler S, Marchal M, Coppee JY, Chandler M, Bonnefoy V, Brochier-Armanet C, Barakat M, Barbe V, Battaglia-Brunet F, Bruneel O, Bryan CG, Cleiss-Arnold J, Cruveiller S, Erhardt M, Heinrich-Salmeron A et al (2010) Structure, function and evolution of the Thiomonas spp. genome. PLoS Genet 6(2):e1000859CrossRefGoogle Scholar
- Lett M, Paknikar K, Lievremont D (2001) A simple and rapid method for arsenite and arsenate speciation. Process Metall 11:541–546Google Scholar
- Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193(1):265–275Google Scholar
- Mahtani S, Mavinkurve S (1979) Microbial purification of longifolene: a sesquiterpene. J Ferment Technol 57:529–533Google Scholar
- Muller D, Medigue C, Koechler S, Barbe V, Barakat M, Talla E, Bonnefoy V, Krin E, Arsene-Ploetze F, Carapito C, Chandler M, Cournoyer Cruveiller S, Dossat C, Duval S, Heymann M, Leize E, Lieutaud A, Lievremont D et al (2007) A tale of two oxidation states: bacterial colonization of arsenic-rich environments. PLoS Genet 3(4):e53CrossRefGoogle Scholar
- Rai A, Tripathi P, Dwivedi S, Dubey S, Shri M, Kumar S, Tripathi PK, Dave R, Kumar A, Singh R, Adhikari B, Bag M, Tripathi RD, Trivedi PK, Chakrabarty D, Tuli R (2011) Arsenic tolerance in rice (Oryza sativa) have a predominant role in transcriptional regulation of a set of genes including sulphur assimilation pathway and antioxidant system. Chemosphere 82:986–995CrossRefGoogle Scholar
- Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, New YorkGoogle Scholar
- Stolz JF, Basu P, Oremland RS (2010) Microbial arsenic metabolism: new twists on an old poison. Microbe 5:39–53Google Scholar
- WHO (1993) Guidelines for drinking water quality. recommendations, 2nd edn. World Health Organization, GenevaGoogle Scholar