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Dominance of sphingomonads in a copper-exposed biofilm community for groundwater treatment

(2007) MICROBIOLOGY-SGM. 153(2). p.325-337
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Abstract
The structure, biological activity and microbial biodiversity of a biofilm used for the removal of copper from groundwater were studied and compared with those of a biofilm grown under copper-free conditions. A laboratory-scale submerged fixed biofilter was fed with groundwater (2.3 l h(-1)) artificially polluted with Cu(II) (15 mg l(-1)) and amended with sucrose (150 mg l(-1)) as carbon source. Between 73 and 90% of the Cu(II) was removed from water during long-term operation (over 200 days). The biofilm was a complex ecosystem, consisting of eukaryotic and prokaryotic micro-organisms. Scanning electron microscopy revealed marked structural changes in the biofilm induced by Cu(II), compared to the biofilm grown in absence of the heavy metal. Analysis of cell-bound extracellular polymeric substances (EPS) demonstrated a significant modification of the composition of cell envelopes in response to Cu(II). Transmission electron microscopy and energy-dispersive X-ray microanalysis (EDX) showed that copper bioaccumulated in the EPS matrix by becoming bound to phosphates and/or silicates, whereas copper accumulated only intracytoplasmically in cells of eukaryotic microbes. Cu(II) also decreased sucrose consumption, ATP content and alkaline phosphatase activity of the biofilm. A detailed study of the bacterial community composition was conducted by 16S rRNA-based temperature gradient gel electrophoresis (TGGE) profiling, which showed spatial and temporal stability of the species diversity of copper-exposed biofilms during biofilter operation. PCR reamplification and sequencing of 14 TGGE bands showed the prevalence of alphaproteobacteria, with most sequences (78%) affiliated to the Sphingomonadaceae. The major cultivable colony type in plate counts of the copper-exposed biofilm was also identified as that of Sphingomonas sp. These data confirm a major role of these organisms in the composition of the Cu(II)-removing community.
Keywords
16S RIBOSOMAL-RNA, GRADIENT GEL-ELECTROPHORESIS, HEAVY-METALS, WASTE-WATER, MICROBIAL COMMUNITIES, CONTAMINATED SOILS, BACTERIA, GENES, PCR, TOXICITY

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Citation

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Chicago
Vilchez Vargas, Ramiro, C Pozo, MA Gómez, B Rodelas, and J González-López. 2007. “Dominance of Sphingomonads in a Copper-exposed Biofilm Community for Groundwater Treatment.” Microbiology-sgm 153 (2): 325–337.
APA
Vilchez Vargas, R., Pozo, C., Gómez, M., Rodelas, B., & González-López, J. (2007). Dominance of sphingomonads in a copper-exposed biofilm community for groundwater treatment. MICROBIOLOGY-SGM, 153(2), 325–337.
Vancouver
1.
Vilchez Vargas R, Pozo C, Gómez M, Rodelas B, González-López J. Dominance of sphingomonads in a copper-exposed biofilm community for groundwater treatment. MICROBIOLOGY-SGM. 2007;153(2):325–37.
MLA
Vilchez Vargas, Ramiro, C Pozo, MA Gómez, et al. “Dominance of Sphingomonads in a Copper-exposed Biofilm Community for Groundwater Treatment.” MICROBIOLOGY-SGM 153.2 (2007): 325–337. Print.
@article{4421187,
  abstract     = {The structure, biological activity and microbial biodiversity of a biofilm used for the removal of copper from groundwater were studied and compared with those of a biofilm grown under copper-free conditions. A laboratory-scale submerged fixed biofilter was fed with groundwater (2.3 l h(-1)) artificially polluted with Cu(II) (15 mg l(-1)) and amended with sucrose (150 mg l(-1)) as carbon source. Between 73 and 90\% of the Cu(II) was removed from water during long-term operation (over 200 days). The biofilm was a complex ecosystem, consisting of eukaryotic and prokaryotic micro-organisms. Scanning electron microscopy revealed marked structural changes in the biofilm induced by Cu(II), compared to the biofilm grown in absence of the heavy metal. Analysis of cell-bound extracellular polymeric substances (EPS) demonstrated a significant modification of the composition of cell envelopes in response to Cu(II). Transmission electron microscopy and energy-dispersive X-ray microanalysis (EDX) showed that copper bioaccumulated in the EPS matrix by becoming bound to phosphates and/or silicates, whereas copper accumulated only intracytoplasmically in cells of eukaryotic microbes. Cu(II) also decreased sucrose consumption, ATP content and alkaline phosphatase activity of the biofilm. A detailed study of the bacterial community composition was conducted by 16S rRNA-based temperature gradient gel electrophoresis (TGGE) profiling, which showed spatial and temporal stability of the species diversity of copper-exposed biofilms during biofilter operation. PCR reamplification and sequencing of 14 TGGE bands showed the prevalence of alphaproteobacteria, with most sequences (78\%) affiliated to the Sphingomonadaceae. The major cultivable colony type in plate counts of the copper-exposed biofilm was also identified as that of Sphingomonas sp. These data confirm a major role of these organisms in the composition of the Cu(II)-removing community.},
  author       = {Vilchez Vargas, Ramiro and Pozo, C and G{\'o}mez, MA and Rodelas, B and Gonz{\'a}lez-L{\'o}pez, J},
  issn         = {1350-0872},
  journal      = {MICROBIOLOGY-SGM},
  language     = {eng},
  number       = {2},
  pages        = {325--337},
  title        = {Dominance of sphingomonads in a copper-exposed biofilm community for groundwater treatment},
  url          = {http://dx.doi.org/10.1099/mic.0.2006/002139-0},
  volume       = {153},
  year         = {2007},
}

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