Perth Laboratory – Public Seminar Series 2009

Microbial oxidation of metal sulphide crystals: fundamentals of the microbe-mineral surface interaction

Dr Kayley Usher
CSIRO Office of the Chief Executive Post-doctoral Fellow
CSIRO Land and Water

Thursday 27 August 2009 at 3.30pm, CSIRO Auditorium

Abstract

About 80% of the remaining global copper reserves exist in the mineral chalcopyrite, a metal sulphide. Although relatively abundant, chalcopyrite usually exists as a low-grade ore that is difficult to extract copper from in a cost effective manner using conventional methods. Bioleaching of chalcopyrite using acid-loving microbes offers an alternative, and has economic and environmental benefits as smelting and refining are no longer required. A variety of acidophilic microbes are used in the process, deriving energy by oxidising Fe²⁺ and reduced S compounds, and significantly accelerating the release of Cu via the generation of protons and Fe³⁺, a mineral sulphide-oxidising agent.

In an on-going project mesophilic bacteria Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans and thermoacidophilic archaea such as Metallosphaera hakonensis are being investigated using high resolution electron microscopy techniques to understand the fundamental aspects of the chemistry and microbiology of the microbe-mineral interaction during chalcopyrite bioleaching.

About the speaker

Dr Kayley Usher joined CSIRO Land and Water in 2008 as an OCE Post-Doctoral Fellow. She has a PhD in Microbiology from the University of Western Australia where she investigated sponge sex and symbiosis. She has also been involved in research to investigate haploid embryogenesis in grain legumes at the University of WA Centre for Legumes in Mediterranean Agriculture. She won a University of Western Australia Postgraduate Award in 1999 and a Research Grant in 2007.

Dr Usher is currently utilising her skills in optical and electron microscopy to investigate the microbe/mineral interface during bioleaching of chalcopyrite for the Australian minerals industry.

This research is being delivered through CSIRO's Minerals Down Under Flagship

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