Microbial diversity of Emalahleni mine water in South Africa and tolerance ability of the predominant organism to vanadium and nickel

PLoS One. 2014 Jan 22;9(1):e86189. doi: 10.1371/journal.pone.0086189. eCollection 2014.

Abstract

The present study aims firstly at determining the microbial diversity of mine-water collected in Emalahleni, South Africa and secondly isolating and characterizing the most dominant bacterial species found in the mine water in terms of its resistance to both V(5+) and Ni(2+) in a modified wastewater liquid media. The results revealed a microbial diversity of 17 orders, 27 families and 33 genera were found in the mine-water samples with Marinobacteria (47.02%) and Anabaena (17.66%) being the most abundant genera. Considering their abundance in the mine-water samples, a species of the Marinobacter genera was isolated, identified, and characterised for metal tolerance and removal ability. The MWI-1 isolate (Marinobacter sp. MWI-1 [AB793286]) was found to be closely related to Marinobacter goseongensis at 97% of similarity. The isolate was exposed to various concentrations of Ni(2+) and V(5+) in wastewater liquid media and its tolerance to metals was also assessed. The MWI-1 isolate could tolerate V(5+) and Ni(2+) separately at concentrations (in terms of MIC) up to 13.41 ± 0.56 mM and 5.39 ± 0.5 mM at pH 7, whereas at pH 3, the tolerance limit decrease to 11.45 ± 0.57 mM and 2.67 ± 0.1 mM, respectively. The removal of V(5+) and Ni(2+) in liquid media was noted to gradually decrease with a gradual increase of the test metals. A significant difference (p<0.05) between V(5+) and Ni(2+) removal was noted. Marinobacter sp. MWI-1 achieved the maximum permissible limit of 0.1 mg-V(5+)/L prescribed by UN-FAO at 100 mg/L, while at 200 mg/L only V(5+) was removed at approximately 95% and Ni(2+) at 47%. This study suggests that mine-water indigenous microorganisms are the best solution for the remediation of polluted mine water.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Biological*
  • Biodiversity
  • Humans
  • Hydrogen-Ion Concentration
  • Industrial Waste*
  • Metagenome
  • Microbiota*
  • Molecular Sequence Data
  • Nickel* / toxicity
  • Phylogeny
  • RNA, Ribosomal, 16S
  • South Africa
  • Vanadium* / toxicity
  • Waste Water / microbiology*
  • Water Microbiology*

Substances

  • Industrial Waste
  • RNA, Ribosomal, 16S
  • Waste Water
  • Vanadium
  • Nickel

Associated data

  • GENBANK/AB793286

Grant support

The authors are grateful to the National Research Foundation (NRF) for the funding of this project (Grant number: M590). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.