Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jan 15;11(1):222.
doi: 10.3390/microorganisms11010222.

Interesting Halophilic Sulphur-Oxidising Bacteria with Bioleaching Potential: Implications for Pollutant Mobilisation from Mine Waste

Chiamaka Belsonia Opara  1 , Nor Kamariah  2 , Jeroen Spooren  2 , Katrin Pollmann  1 , Sabine Kutschke  1
Affiliations

Interesting Halophilic Sulphur-Oxidising Bacteria with Bioleaching Potential: Implications for Pollutant Mobilisation from Mine Waste

Chiamaka Belsonia Opara et al. Microorganisms. .

Abstract

For many years, research on the microbial-dissolution of metals from ores or waste materials mainly focussed on the study of acidophilic organisms. However, most acidophilic bioleaching microorganisms have limited tolerance to high chloride concentrations, thereby requiring fresh water for bioleaching operations. There is a growing interest in the use of seawater for leaching purposes, especially in regions with less access to fresh water. Consequently, there is a need to find halophilic organisms with bioleaching potentials. This study investigated the bioleaching potentials of four moderately halophilic sulphur-oxidising bacteria: Thiomicrospira cyclica, Thiohalobacter thiocyanaticus, Thioclava electrotropha and Thioclava pacifica. Results revealed T. electrotropha and T. pacifica as the most promising for bioleaching. Pure cultures of the two Thioclava strains liberated about 30% Co, and between 8-17% Cu, Pb, Zn, K, Cd, and Mn from a mine waste rock sample from the Neves Corvo mine, Portugal. Microwave roasting of the waste rock at 400 and 500 °C improved the bioleaching efficiency of T. electrotropha for Pb (13.7 to 45.7%), Ag (5.3 to 36%) and In (0 to 27.4%). Mineralogical analysis of the bioleached residues using SEM/MLA-GXMAP showed no major difference in the mineral compositions before or after bioleaching by the Thioclava spp. Generally, the bioleaching rates of the Thioclava spp. are quite low compared to that of the conventional acidophilic bioleaching bacteria. Nevertheless, their ability to liberate potential pollutants (metal(loid)s) into solution from mine waste raises environmental concerns. This is due to their relevance in the biogeochemistry of mine waste dumps, as similar neutrophile halophilic sulphur-oxidising organisms (e.g., Halothiobacillus spp.) have been isolated from mine wastes. On the other hand, the use of competent halophilic microorganisms could be the future of bioleaching due to their high tolerance to Cl- ions and their potential to catalyse mineral dissolution in seawater media, instead of fresh water.

Keywords: Thioclava electrotropha; Thioclava pacifica; Thiohalobacter thiocyanaticus; Thiomicrospira cyclica; bioleaching; halophilic sulphur-oxidising bacteria; mine waste rock; pollutant mobilisation.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Figures

Figure A1
Figure A1
The evolution of pH (a), Fe (b) and sulphate (SO42−) (c) concentrations during the bioleaching of the Neves Corvo waste rock (NC_01) by the Thioclava consortium. Values are the average of duplicate flasks ± standard deviations.
Figure A2
Figure A2
The evolution of pH (a), Fe (b) and sulphate (SO42−) (c) concentrations during a process optimisation experiment (weekly serial addition of NC_01 and partial nutrient replacement) via one-step bioleaching (1SB) and two-step bioleaching (2SB) of the Neves Corvo waste rock (NC_01) via by T. electrotropha and T. pacifica. Values are the average of duplicate flasks ± standard deviations.
Figure A3
Figure A3
The evolution of pH (a–c), Fe (d–f) and SO42− (g–i) concentrations during the bioleaching of the microwave-roasted (at 400, 500 and 600°C) Neves Corvo waste rock (NC_01) by T. electrotropha via one-step bioleaching (1SB), two-step bioleaching (2SB) and the abiotic control (AC). Values are the average of duplicate flasks ± standard deviations.
Figure 1
Figure 1
The evolution of pH, Fe and sulphate (SO42−) concentrations during the bioleaching of the Neves Corvo waste rock (NC_01) by T. cyclica (a–c), T. thiocyanaticus (d–f), T. electrotropha (g–i) and T. pacifica (j–l). Values are the average of duplicate flasks ± standard deviations.
Figure 2
Figure 2
Maximum percentages of metal(loid)s extracted from the Neves Corvo waste rock (NC_01) by four halophilic sulphur-oxidising bacterial strains. Values are the average of duplicate flasks ± standard deviations.
Figure 3
Figure 3
XRD scans of the Neves Corvo waste rock (NC_01) before and after microwave roasting at 400, 500, and 600 °C.
Figure 4
Figure 4
Maximum percentage of metal(loid)s extracted from the Neves Corvo waste rock (NC_01) by the Thioclava spp. via four process optimisation methods. Values are the average of duplicate flasks ± standard deviations.
See this image and copyright information in PMC

References

    1. Vriens B., Plante B., Seigneur N., Jamieson H. Mine Waste Rock: Insights for Sustainable Hydrogeochemical Management. Minerals. 2020;10:728. doi: 10.3390/min10090728. - DOI
    1. Amos R.T., Blowes D.W., Bailey B.L., Sego D.C., Smith L., Ritchie A.I.M. Waste-rock hydrogeology and geochemistry. Appl. Geochem. 2015;57:140–156. doi: 10.1016/j.apgeochem.2014.06.020. - DOI
    1. Falagán C., Grail B.M., Johnson D.B. New approaches for extracting and recovering metals from mine tailings. Miner. Eng. 2017;106:71–78. doi: 10.1016/j.mineng.2016.10.008. - DOI
    1. Brierley C.L., Brierley J.A. Progress in bioleaching: Part B: Applications of microbial processes by the minerals industries. Appl. Microbiol. Biotechnol. 2013;97:7543–7552. doi: 10.1007/s00253-013-5095-3. - DOI - PubMed
    1. Rawlings D.E. Heavy metal mining using microbes. Annu. Rev. Microbiol. 2002;56:65–91. doi: 10.1146/annurev.micro.56.012302.161052. - DOI - PubMed

LinkOut - more resources