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Understanding biological Understanding biological uranium reductionuranium reduction
Sherilee PalmSherilee Palm
Energy Postgraduate Conference 2013Energy Postgraduate Conference 2013
Supervisor: Prof E. van HeerdenCo-supervisors: Errol Cason
Dr. D. Opperman
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IntroductionIntroduction• Microbe – metal interactions:
• Systems
Bioaccumulation
Biomineralization
Biosorption
Bioreduction
(Beliaev et al., 2001)
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IntroductionIntroduction
(Vaughan and Lloyd, 2011)
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AimsAims
• Assess the microbial diversity of uranium and thorium contaminated water.
• Use metal-reducing bacteria as biocatalysts for uranium and thorium bioreduction.
• Use known genomes of metal reducers to elucidate metabolic capabilities.
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DiversityDiversity
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To understand how a biological process occurs, two routes can be followed:
Let the microorganism do the work
Assess the genome of the
microorganism to determine if it has
the correct tools to do the work.
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Uranium reductionUranium reduction
U (IV)U (VI)
U(VI)– Mobile– Soluble– Toxic
• Mutagen & carcinogenic
U(IV) – Immobile– Insoluble– Less toxic
(Payne, 2005; Cason et al., 2012; Abdelouas et al., 2000)
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Enzymatic U(VI) reductionEnzymatic U(VI) reductionThe Lovley Model:
(Lovley et al., 1993; Cason et al., 2012)
Peptide ABC transporter, peptide-binding protein
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External electron transport External electron transport systemssystems
(Valocchi, 2011)
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ConclusionsConclusions•Microbial encounters with metals in the environment are
inevitable, consequently microbes have developed defence
mechanisms against metal toxicity.
•A mechanistic understanding of uranium (and thorium)
bioreduction/biosorption could aid in devising an effective
and economically feasible bioremediation process for the
removal/separation of these metals.
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AcknowledgementsAcknowledgements• University if the Free State
• Prof Esta van Heerden
• Extreme biochemistry
• NRF (SANHARP)
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T: +27(0)51 401 9039 | [email protected]
Thank youDankie
¡graciasشكرا
DěkujiDankeGrazie
gratias ago vosKe a leboha
T: +27 (0)51 401 9897 [email protected]