Tolerance and growth kinetics of bacteria isolated from gold and gemstone mining sites in response to heavy metal concentrations

Response and growth kinetics of microbes in contaminated medium are useful indices for the screening and selection of tolerant species for eco-friendly bio-augmentative remediation of polluted environments. In this study, the heavy metal (HM) tolerance, bioaccumulation and growth kinetics of seven b...

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Bibliographic Details
Published in:Journal of environmental management 2018-04, Vol.212, p.357-366
Main Authors: Oladipo, Oluwatosin Gbemisola, Ezeokoli, Obinna Tobechukwu, Maboeta, Mark Steve, Bezuidenhout, Jacobus Johannes, Tiedt, Louwrens R., Jordaan, Anine, Bezuidenhout, Cornelius Carlos
Format: Article
Language:English
Subjects:
Bacteria - growth & development
Bacterial metal tolerance
Biodegradation
Bioremediation
Environmental contaminant
Environmental Monitoring
Gold
Kinetics
Metal bioaccumulation
Metals, Heavy - toxicity
Mining
Mining site
RNA, Ribosomal, 16S
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Summary:Response and growth kinetics of microbes in contaminated medium are useful indices for the screening and selection of tolerant species for eco-friendly bio-augmentative remediation of polluted environments. In this study, the heavy metal (HM) tolerance, bioaccumulation and growth kinetics of seven bacterial strains isolated from mining sites to 10 HMs (Cd, Hg, Ni, Al, Cr, Pb, Cu, Fe, Mn and Zn) at varied concentrations (25–600 mgL−1) were investigated. The isolates were phylogenetically (16S rRNA gene) related to Lysinibacillus macroides, Achromobacter spanius, Bacillus kochii, B. cereus, Klebsiella pneumoniae, Pseudomonas mosselii and P. nitroreducens. Metal tolerance, effects on lag phase duration and growth rates were assessed using the 96-well micro-titre method. Furthermore, metal bioaccumulation and quantities within cells were determined by transmission electron microscopy and electron dispersive x-ray analyses. Tolerance to Ni, Pb, Fe and Mn occurred at highest concentrations tested. Growth rates increased with increasing Fe concentrations, but reduced significantly (p  Pb > Mn > Cr=Al > Cd > Cu > Zn > Hg.•Multi-metal tolerance trend of isolates was BC > BK > AS > PN=PM > KP > LM.•Micrographs depicted intra-cellular metal accumulations with no cell morphology distortions.•Findings indicate heavy metal tolerance, hence clean-up traits of bacterial strains.
ISSN:0301-4797
1095-8630
DOI:10.1016/j.jenvman.2018.01.038