Uranium (VI) recovery from saline environment by a marine unicellular cyanobacterium, Synechococcus elongatus

Abstract

Sequestration of uranium from simulated sea water and reverse osmosis concentrates by the marine cyanobacterium, Synechococcus elongatus was assessed. Short term experiments established removal of 90–98 % uranium by the strain from simulated sea water containing 13 nM uranyl carbonate at pH 7.8, resulting in a loading of 7–42 μg U g−1 over a period of 1–5 days respectively. Long term experiments involving repeated exposure of Synechococcus biomass to fresh simulated sea water every third day, showed a loading of 2,960 μg U g−1 in 4 weeks. Nearly 85–90 % of cell bound uranium could be desorbed using 0.1 N HCl. The organism could sequester uranium (13,306 μg U g−1 in 24 h) from aqueous solutions supplemented with 0.6 M NaCl and 21 μM [UO2(CO3)2]2− at pH 7.8. The results demonstrate noteworthy potential of this organism for harnessing uranium from marine environments.