PERSPECTIVES IN BIODEGRADATION OF ALKANES AND PCBS

Mixtures of indigenous soil bacteria were applied to remediate local g round waters and soil polluted with petroleum derived substances. Impl ementation of three months remediation protocols resulted in a decline of the amount of petroleum derived contaminants from an initial conce ntration of 1-10 g.kg(-1) soil dry weight to an average of 0.25 g.kg(- 1) soil dry weight. We also studied genetic and biochemical properties of the bacterial strain Pseudomonas C12B. It was originally isolated for its ability to utilise alkylsulfates and alkylbenzensulfonates as the sole source of carbon and energy. PCB biodegradation was studied u sing two biological models, bacterial co-cultures and plant cells cult ivated in vitro. An industrial mixture of polychlorinated biphenyls (D elor 103) containing about 60 congeners of different degrees of chlori nation (an average of three chlorines per biphenyl molecule) was used. Bacterial co-cultures acquired from enrichment protocols were tested in laboratory and semi-pilot experiments. Pilot experiments were perfo rmed in a two step process in a ground water decontamination unit (wor king volume 5m(3)) which was operated semi-continuously. After 45 days of operation the initial PCB concentration had decreased to 20%. In l aboratory experiments PCB degradation using plant cells cultivated in vitro was also performed. Different cultures of various species differ ing in their growth parameters and morphology (amorphous, differentiat ed shoot forming or ''hairy root''), transformed or nontransformed by Agrobacterium, were used. Differentiated or hairy root cultures exhibi ted better degradative abilities than undifferentiated amorphous cultu res.