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Titel (primär) Effect of electrokinetic transport on the vulnerability of PAH-degrading bacteria in a model aquifer
Autor Shi, L.; Müller, S.; Harms, H.; Wick, L.Y.;
Journal / Serie Environmental Geochemistry and Health
Erscheinungsjahr 2008
Department UMB;
Band/Volume 30
Heft 2
Sprache englisch;
Keywords Bioavailability; Electro-bioremediation; Electrokinetics; Flow cytometry; Propidium iodide; Cell viability; Polycyclic aromatic hydrocarbons
Abstract There has been increasing interest in employing electro-bioremediation, a hybrid technology of bioremediation and electrokinetics, to overcome the low bioavailability of hydrophobic organic contaminants (HOC) by homogenizing sorption-retarded HOC and immobilised microorganisms. Present electro-remediation approaches mainly aim at macroscale pollutant extraction and tend to neglect possible impacts of direct current (DC) on the physiology of microorganisms. The effect of weak electric fields (X = 1 V cm-1) on the fitness of electrokinetically dispersed fluorene-degrading Sphingomonas sp. LB126 in bench-scale model aquifers was investigated by flow cytometry using propidium iodide (PI) as an indicator that distinguishes between PI-permeable (cells with porous membranes, i.e. dead or vulnerable) and PI-impermeable bacteria. After 15.5 h of DC treatment 56% of all cells recovered were dispersed at the centimetre scale relative to 29% in the absence of DC. There was no overall negative effect of the 15.5-h DC treatment on cell vulnerability, as 7.0% of the DC-treated bacteria exhibited PI-staining compared to 6.5% of the control population. Minor differences were observed in the subpopulation that had been mobilised by electroosmosis with an approximately twofold increase in the percentage of PI-stained cells relative to the control. Enhanced PI staining did not correlate with reduced culturability of the cells on rich-medium agar plates. Relative to the control, DC-treated cells mobilised by electroosmosis were threefold more culturable, confirming earlier data that that PI-cell membrane permeability does not always indicate reduced viability of oligotrophic environmental bacteria. Our findings suggest that electrokinetics is a valuable mechanism to transport viable and culturable polycyclic aromatic hydrocarbon (PAH)-degrading bacteria in soil or sediments.
ID 1454
dauerhafte UFZ-Verlinkung
Shi, L., Müller, S., Harms, H., Wick, L.Y. (2008):
Effect of electrokinetic transport on the vulnerability of PAH-degrading bacteria in a model aquifer
Environ. Geochem. Health 30 (2), 177 - 182