Cellular accumulation of cesium in the unicellular red alga Galdieria sulphuraria under mixotrophic conditions
As a consequence of the Fukushima Daiichi Nuclear Power Plant accident which occurred in Japan in 2011, huge amounts of radioactive cesium (Cs) spread across a large area at low concentrations. Bioremediation is known as an effective method for the recovery and concentration of metals at low concentrations. In the present study we showed that G. sulphuraria cells recovered 52 ± 15% of the Cs present in a potassium-deficient medium containing 30 μg L−1 Cs in 10 days. Because of the advantages in biotechnological use, G. sulphuraria is a good candidate for the decontamination of radioactive Cs. In G. sulphuraria cells, Cs was accumulated specifically under mixotrophic condition of the three different culture conditions used (autotorophic, mixotrophic, and heterotrophic condition). Cells in the early logarithmic phase of growth did not accumulate Cs, whereas those in the late logarithmic phase did. Cs accumulated in the cell exists mainly in a soluble form (e.g., salt, chelating complex).
KeywordsBioremediation Galdieria sulphuraria Rhodophyceae Radioactive cesium Biological concentration
The authors would like to thank the radiation safety management and chemical analysis division at University of Tsukuba for their technical support.
This study was supported by a research grant from Takahashi Industrial and Economic Research Foundation (to A. M.) and JSPS KAKENHI Grant Number 18 K05922 (to A. M.) and Grant-in-Aid for Exploratory Research from JSPS (25550060) and by Great East Japan Earthquake Recovery and Rebirth Assistance Program in 2012 and 2013 from University of Tsukuba, Japan.
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