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Journal of Biotechnology
Vol. 127,No: xx, 2007, Pages: 434–442

Arsenic resistance and removal by marine and non-marine bacteria

Mio Takeuchia,*, Hodaka Kawahatab,1, Lallan Prasad Guptab, Noriko Kitab,2 Yuichi Morishitab, Yoshiro Onoc, Takeshi Komaia

Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.


Arsenic resistance and removal was evaluated in nine bacterial strains of marine and non-marine origins. Of the strains tested, Marinomonas communis exhibited the second-highest arsenic resistance with median effective concentration (EC50) value of 510 mg As l-1, and was capable of removing arsenic from culture medium amended with arsenate. Arsenic accumulation in cells amounted to 2290 gAs g-1 (dry weight) when incubated on medium containing 5mgAs l-1 of arsenate. More than half of the arsenic removed was related to metabolic activity: 45% of the arsenic was incorporated into the cytosol fraction and 10% was found in the lipid-bound fraction of the membrane, with the remaining arsenic considered to be adsorbed onto the cell surface. Potential arsenic resistance and removal were also examined in six marine and non-marine environmental water samples. Of the total bacterial colony counts, 28–100% of bacteria showed arsenic resistance. Some of the bacterial consortia, especially those from seawater enriched with arsenate, exhibited higher accumulated levels of arsenic than M. communis under the same condition. These results showed that arsenic resistant and/or accumulating bacteria are widespread in the aquatic environment, and that arsenic-accumulating bacteria such as M. communis are potential candidates for bioremediation of arsenic contaminated water.

Keywords: Arsenic, Removal, Accumulation, Resistance, Bioremediation, Bacteria,Marinomonas communis,non-marine origins,marine bacteria,bioremediation.

Corresponding author: Tel +81 29 861 2478; fax +81 29 861 8983

E-mail: takeuchi-mio@aist.go.jp


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