A kinetic distribution model of evaporation, biosorption and biodegradation of polychlorinated biphenyls (PCBs) in the suspension of Pseudomonas stutzeri

Kinetics of distribution of PCBs in an active bacterial suspension of Pseud omonas stutzeri was studied by monitoring the evaporated amounts and the co ncentration remaining in the liquid medium with the biomass. To determine t he biodegradation rate constants of the individual congeners of the PCB for mulation Delor 103, a model considering biosorption, evaporation, and prima ry biodegradation constructed previously was used. Rate constants of biodeg radation imply that biodegradation of individual congeners is structure-dep endent process. Biodegradability decreases with increasing number of chlori ne substituents in the molecule, especially if they are in the ortho and pa ra positions. On the other hand, the increasing number of free ortho and me ta positions in the biphenyl molecule leads to better biodegradability. For a simple empirical determination of the influence of the chlorine substitu tion pattern on biodegradability, the di- and trichlorobiphenyl rate consta nts of biodegradation were analysed.