The contamination of natural systems by mining activities, which can generate large volumes of chemically hazardous waste, has the potential to negatively impact environmental and human health. One such process, the addition of cyanide to extract gold from ore, results in the production of large volumes of thiocyanate (SCN-) contaminated wastewater. Although recalcitrant to most chemical techniques, SCN- can be biodegraded by a number of microorganisms. Indeed, SCN- and its sulfur and nitrogen containing degradation products also occur at low levels in natural systems and act as sulfur, nitrogen and/or carbon source to microbial communities. Several biotechnology approaches have recently been proposed to exploit this metabolic trait for the treatment of industrial effluent. Understanding the complex community dynamics and its response to changing environmental conditions will enable the development of more resilient and efficient biotechnology systems, while revealing fundamental insights in to the cycling of sulfur and nitrogen containing C1 compounds.

This talk will focus on an on-going project to understand, optimize and implement an effective SCN- bioremediation strategy for contaminated mine sites. Through this work we have explored the potential for in situ SCN- biodegradation in gold mine tailings and also tested a bioreactor approach to treating SCN- contaminated water. To complement chemical analysis we have employed genome-resolved metagenomic analysis of the microbial communities inhabiting these systems, revealing which community members are capable of degrading SCN- and it metabolites, and more widely the metabolic activities underpinning these systems. We were also able to observe how the community responds to perturbations in key environmental variables and what impact this has on the effectiveness of the approach. These findings are now being implemented at a larger scale as part of a SCN- bioremediation strategy at a Victorian gold mine.

Biography:  Dr Watts is a Postdoctoral Fellow in the Geomicrobiology group in Earth Sciences, University of Melbourne, having joined the group after completing his PhD in 2014 at the University of Manchester, UK. He has a background in geomicrobiology and geochemistry, with his research primarily focussing on how the metabolic activities of individual microbes and whole microbial communities can be harnessed to help clean up contaminated land and water.



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