Transcript Palm_S_final - Energy Postgraduate Conference 2013

Understanding biological uranium
reduction
Sherilee Palm
Supervisor: Prof E. van Heerden
Co-supervisors: Errol Cason
Dr. D. Opperman
Energy Postgraduate Conference 2013
Introduction
•
•
Microbe – metal interactions:
Bioaccumulation
Biosorption
Biomineralization
Bioreduction
Systems
(Beliaev et al., 2001)
Introduction
(Vaughan and Lloyd, 2011)
Aims
• 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.
Diversity
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.
Uranium reduction
U(VI)
– Mobile
– Soluble
– Toxic
• Mutagen & carcinogenic
U (VI)
(Payne, 2005; Cason et al., 2012; Abdelouas et al., 2000)
U(IV)
– Immobile
– Insoluble
– Less toxic
U (IV)
Enzymatic U(VI) reduction
The Lovley Model:
Peptide ABC transporter, peptide-binding protein
(Lovley et al., 1993; Cason et al., 2012)
External electron transport systems
(Valocchi, 2011)
Conclusions
•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.
Acknowledgements
• University if the Free State
• Prof Esta van Heerden
• Extreme biochemistry
• NRF (SANHARP)
Thank you
Dankie
¡gracias
‫شكرا‬
Děkuji
Danke
Grazie
gratias ago vos
Ke a leboha
T: +27(0)51 401 9039 | [email protected]
T: +27 (0)51 401 9897
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