**3. Conclusions**

Many responses have been observed and confirmed in bacteria that counteract the effects of toxic environmental organic pollutants. Rigidification of the cell membrane is a consequence of cell adaptation mechanisms. The alterations in cytoplasmic membrane maintain ratio between bilayer and nonbilayer phospholipids (prevention against the environmentally induced formation of interdigitated structure) and keep the optimal phospholipids ordering to stabilize membrane fluidity. Another mechanism to protect bacterial cell is the efflux of toxic compounds from the membrane compartment. Toxic compounds affect not only cytoplasmic lipids but also cell proteins. This results in the development of special protein repair mechanisms by bacteria. Study of these adaptation mechanisms was the first step in selection of appropriate resistant bacterial strains, usually isolated from the contaminated area, and used for bioremediation application. Successful environment decontamination using biological approaches requires bacterial strains that can degrade particular (one or more) contaminants. Moreover, such strains have to be able to survive and adapt to adverse environment. Next step included the study of degradation potential of the most resistant strains. The resistant strain/consortium possessing appropriate degradation enzymes is the essential element of successful bioremediation. Both assisted bioremediation approaches, bioaugmentation and biostimulation, revealed to be perspective and prospective approaches of PCB decontamination. The degradation studies in artificial precisely defined matrices under the laboratory conditions (microcosms) could be applied in macrocosm and then after verification of strain/consortia degradation efficacy and survival ability and characterization of the optimal conditions for the successful decontamination process used in the field conditions.
