Metal Interactions with Microbial Biofilms in Acidic and Neutral pH Environments.

  • Ferris F
  • Schultze S
  • Witten T
 et al. 
  • 78

    Readers

    Mendeley users who have this article in their library.
  • N/A

    Citations

    Citations of this article.

Abstract

Microbial biofilms were grown on strips of epoxy-impregnated filter paper submerged at four sites in water contaminated with metals from mine wastes. At two sample stations, the water was acidic (pH 3.1); the other sites were in a lake restored to a near neutral pH level by application of a crushed limestone slurry. During a 17-week study period, planktonic bacterial counts increased from 10 to 10 CFU/ml at all sites. Biofilm counts increased rapidly over the first 5 weeks and then leveled to 10 CFU/cm in the neutral pH system and 10 CFU/cm at the acidic sites. In each case, the biofilms bound Mn, Fe, Ni, and Cu in excess of the amounts adsorbed by control strips covered with nylon filters (pore size, 0.22 mum) to exclude microbial growth; Co bound under neutral conditions but not under acidic conditions. Conditional adsorption capacity constants, obtained graphically from the data, showed that biofilm metal uptake at a neutral pH level was enhanced by up to 12 orders of magnitude over acidic conditions. Similarly, adsorption strength values were usually higher at elevated pH levels. In thin sections of the biofilms, encapsulated bacterial cells were commonly found enmeshed together in microcolonies. The extracellular polymers often contained iron oxide precipitates which generated weak electron diffraction patterns with characteristic reflections for ferrihydrite (Fe(2)O(3) . H(2)O) at d equaling 0.15 and 0.25 nm. At neutral pH levels, these deposits incorporated trace amounts of Si and exhibited a granular morphology, whereas acicular crystalloids containing S developed under acidic conditions.

Author-supplied keywords

  • BACTERIA
  • ELECTRON MICROSCOPY
  • INCOMPLETE
  • LAKE RESTORATION
  • LIMESTONE
  • PLANKTON
  • PLANKTON N1 - N2 -

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • FG Ferris

  • S Schultze

  • TC Witten

  • WS Fyfe

  • TJ Beveridge

  • S Schultz

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free