AUTHOR=Romero-González Maria , Nwaobi Bennett C. , Hufton Joseph M. , Gilmour Daniel J. 

TITLE=Ex-situ Bioremediation of U(VI) from Contaminated Mine Water Using Acidithiobacillus ferrooxidans Strains

JOURNAL=Frontiers in Environmental Science

VOLUME=4

YEAR=2016

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2016.00039

DOI=10.3389/fenvs.2016.00039

ISSN=2296-665X

ABSTRACT=<p>The <italic>ex-situ</italic> bioremoval of U(VI) from contaminated water using <italic>Acidithiobacillus ferrooxidans</italic> strain 8455 and 13538 was studied under a range of pH and uranium concentrations. The effect of pH on the growth of bacteria was evaluated across the range 1.5–4.5 pH units. The respiration rate of <italic>At. ferrooxidans</italic> at different U(VI) concentrations was quantified as a measure of the rate of metabolic activity over time using an oxygen electrode. The biosorption process was quantified using a uranyl nitrate solution, U-spiked growth media, and U-contaminated mine water. The results showed that both strains of <italic>At. ferrooxidans</italic> are able to remove U(VI) from solution at pH 2.5–4.5, exhibiting a buffering capacity at pH 3.5. The respiration rate of the micro-organism was affected at U(VI) concentration of 30 mg L<sup>−1</sup>. The kinetics of the sorption fitted a pseudo-first order equation, and depended on the concentration of U(VI). The <italic>K</italic><sub><italic>D</italic></sub> obtained from the biosorption experiments indicated that strain 8455 is more efficient for the removal of U(VI). A bioreactor designed to treat a solution of 100 mg U(VI) L<sup>−1</sup> removed at least 50% of the U(VI) in water. The study demonstrated that <italic>At. ferrooxidans</italic> can be used for the <italic>ex-situ</italic> bioremediation of U(VI) contaminated mine water.</p>