Biofilm Shows Spatially Stratified Metabolic Responses to Contaminant Exposure

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · Environmental Microbiology, 14(11):2901-2910

DOI:https://doi.org/10.1111/j.1462-2920.2012.02850.x· OSTI ID:1054430

Cao, Bin; Majors, Paul D; Ahmed, B; Renslow, Ryan S; Sylvia, Crystal P; Shi, Liang; Kjelleberg, Staffan; Fredrickson, Jim K; Beyenal, Haluk

The objective of this study was to elucidate the spatiotemporal responses of live S. oneidensis MR-1 biofilms to U(VI) (uranyl, UO22+) and Cr(VI) (chromate, CrO42-), important environmental contaminants at DOE contaminated sites. Toward this goal, we applied noninvasive nuclear magnetic resonance (NMR) imaging, diffusion, relaxation and spectroscopy techniques to monitor in situ spatiotemporal responses of S. oneidensis biofilms to U(VI) and Cr(VI) exposure in terms of changes in biofilm structures, diffusion properties, and cellular metabolism. Exposure to U(VI) or Cr(VI) did not appear to change the overall biomass distribution but caused changes in the physicochemical microenvironments inside the biofilm as indicated by diffusion measurements. Changes in the diffusion properties of the biofilms in response to U(VI) and Cr(VI) exposure imply a novel function of the extracellular polymeric substances (EPS) affecting the biotransformation and transport of contaminants in the environment. In the presence of U(VI) or Cr(VI), the anaerobic metabolism of lactate was inhibited significantly, although the biofilms were still capable of reducing U(VI) and Cr(VI). Local concentrations of Cr(III)aq in the biofilm suggested relatively high Cr(VI) reduction activities at the top of the biofilm, near the medium-biofilm interface. The depth-resolved metabolic activities of the biofilm suggested higher diversion effects of gluconeogenesis and C1 metabolism pathways at the bottom of the biofilm and in the presence of U(VI). This study provides a noninvasive means to investigate spatiotemporal responses of biofilms, including surface-associated microbial communities in engineering, natural and medical settings, to various environmental perturbations including exposure to environmental contaminants and antimicrobials.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1054430
• Report Number(s): PNNL-SA-83917; KP1702030
• Journal Information: Environmental Microbiology, 14(11):2901-2910, Journal Name: Environmental Microbiology, 14(11):2901-2910
• Country of Publication: United States
• Language: English

Related Subjects

NMR
Shewanella oneidensis
biofilm
chromium.
spatiotemporal responses
uranium