Degradation of PCB congeners by bacterial strains

• DOI: 10.1007/s00253-007-1175-6
• Publication Date: 2007-09-20T08:54:32Z
• Authors: Arno Rein; Margit M. Fernqvist; Philipp Mayer; Stefan Trapp; Martin Bittens; Ulrich Gosewinkel...
• Keywords: 0301 basic medicine; PCB; Bacteria; Willow; Burkholderia; Colony Count, Microbial; Salix; Genetically modified; Pseudomonas fluorescens; Models, Biological; Plant Roots; Polychlorinated Biphenyls; Modelling; Rhizoremediation; Kinetics; 03 medical and health sciences; Biodegradation, Environmental; Cometabolism; Soil contamination; Biodegradation; Monod kinetics; Soil Pollutants; Genetic Engineering; Soil Microbiology

Biological in situ methods are options for the remediation of contaminated sites. An approach to quantify biodegradation by soil bacteria was developed, combining experiment with mathematical modelling. We performed in vitro assays to investigate the potential and kinetics of the wild-type degrader, Burkholderia sp. strain LB400 (expressing bph) and the genetically modified Pseudomonas fluorescens strains F113pcb and F113L::1180 (expressing bph under different promoters) to metabolise individual congeners of polychlorinated biphenyls (PCBs). Kinetics of metabolism was analysed using the Monod model. Results revealed similar patterns of degradable PCB congeners for LB400 and F113L::1180. The degree of PCB degradation was comparable for LB400 and F113L::1180 but was much lower for F113rifpcb. In additional mesocosm experiments with PCB-contaminated soil, the F113 derivatives demonstrated a good survival ability in willow (Salix sp.) rhizosphere. Strain F113L::1180 in combination with willow plants is expected to degrade a large spectrum of PCB congeners in soil. The data from the experiments were used to calculate the time scale of the degradation process in a PCB-contaminated soil. The uncertainty of the model predictions due to the uncertainties of experimental removal velocities and bacterial cell density in soil was quantified.