Activity and viability of polycyclic aromatic hydrocarbon-degrading Sphingomonas sp. LB126 in a DC-electrical field typical for electrobioremediation measures

Microb Biotechnol. 2008 Jan;1(1):53-61. doi: 10.1111/j.1751-7915.2007.00006.x.

Abstract

There has been growing interest in employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics for the treatment of contaminated soil. Knowledge however on the effect of weak electrokinetic conditions on the activity and viability of pollutant-degrading microorganisms is scarce. Here we present data about the influence of direct current (DC) on the membrane integrity, adenosine triphosphate (ATP) pools, physico-chemical cell surface properties, degradation kinetics and culturability of fluorene-degrading Sphingomonas sp. LB126. Flow cytometry was applied to quantify the uptake of propidium iodide (PI) and the membrane potential-related fluorescence intensities (MPRFI) of individual cells within a population. Adenosine tri-phosphate contents and fluorene biodegradation rates of bulk cultures were determined and expressed on a per cell basis. The cells' surface hydrophobicity and electric charge were assessed by contact angle and zeta potential measurements respectively. Relative to the control, DC-exposed cells exhibited up to 60% elevated intracellular ATP levels and yet remained unaffected on all other levels of cellular integrity and functionality tested. Our data suggest that direct current (X=1 V cm(-1); J=10.2 mA cm(-2)) as typically used for electrobioremediation measures has no negative effect on the activity of the polycyclic aromatic hydrocarbon (PAH)-degrading soil microorganism, thereby filling a serious gap of the current knowledge of the electrobioremediation methodology.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Biodegradation, Environmental
  • Electricity
  • Hydrophobic and Hydrophilic Interactions
  • Kinetics
  • Polycyclic Aromatic Hydrocarbons / chemistry
  • Polycyclic Aromatic Hydrocarbons / metabolism*
  • Soil Pollutants / chemistry
  • Soil Pollutants / metabolism
  • Sphingomonas / chemistry*
  • Sphingomonas / metabolism*
  • Surface Properties

Substances

  • Polycyclic Aromatic Hydrocarbons
  • Soil Pollutants
  • Adenosine Triphosphate