The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings

Shafiei, F., Watts, M. P., Pajank, L. and Moreau, J. W. (2021) The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings. Applied Microbiology and Biotechnology, 105(1), pp. 417-427. (doi: 10.1007/s00253-020-10983-4) (PMID:33263791)

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Bioremediation systems represent an environmentally sustainable approach to degrading industrially generated thiocyanate (SCN−), with low energy demand and operational costs and high efficiency and substrate specificity. However, heavy metals present in mine tailings effluent may hamper process efficiency by poisoning thiocyanate-degrading microbial consortia. Here, we experimentally tested the tolerance of an autotrophic SCN−-degrading bacterial consortium enriched from gold mine tailings for Zn, Cu, Ni, Cr, and As. All of the selected metals inhibited SCN− biodegradation to different extents, depending on concentration. At pH of 7.8 and 30 °C, complete inhibition of SCN− biodegradation by Zn, Cu, Ni, and Cr occurred at 20, 5, 10, and 6 mg L−1, respectively. Lower concentrations of these metals decreased the rate of SCN− biodegradation, with relatively long lag times. Interestingly, the microbial consortium tolerated As even at 500 mg L−1, although both the rate and extent of SCN− biodegradation were affected. Potentially, the observed As tolerance could be explained by the origin of our microbial consortium in tailings derived from As-enriched gold ore (arsenopyrite). This study highlights the importance of considering metal co-contamination in bioreactor design and operation for SCN− bioremediation at mine sites.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Moreau, Dr John
Authors: Shafiei, F., Watts, M. P., Pajank, L., and Moreau, J. W.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
Journal Name:Applied Microbiology and Biotechnology
ISSN (Online):1432-0614
Published Online:02 December 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Applied Microbiology and Biotechnology 105(1): 417-427
Publisher Policy:Reproduced under a Creative Commons licence

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