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bioRxiv · 10.1101/2020.06.13.149401

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

Shafiei, F.·Watts, M. P.·Pajank, L.·Moreau, J. W.
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Abstract

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{degrees}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. This study highlights the importance of considering metal co-contamination in bioreactor design and operation for SCN- bioremediation at mine sites. Key pointsO_LIBoth the efficiency and rate of SCN- biodegradation were inhibited by heavy metals, to different degrees depending on type and concentration of metal C_LIO_LIThe autotrophic microbial consortium was capable of tolerating high levels of As C_LI

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Shafiei, F., Watts, M. P., Pajank, L., Moreau, J. W.. 2020-06-13. The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings. https://doi.org/10.1101/2020.06.13.149401

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