The Adaptation Mechanisms of Bacteria Applied in Bioremediation of Hydrophobic Toxic Environmental Pollutants: How Indigenous and Introduced Bacteria Can Respond to Persistent Organic Pollutants-Induced Stress?

The chapter describes the aspects of bioremediation that are related to survival and metabolism of bacterial degraders in the adverse environment contaminated with dangerous hydrophobic chemicals, polychlorinated biphenyls (PCBs). Successful environment decontamination requires bacterial strains that possess appropriate enzymes and are able to degrade particular contaminants. This chapter deals mainly with the adaptation mechanisms that allow bacteria to decrease toxic effects of the dangerous compounds on cytoplasmic membrane as the first contact point of pollutants and the bacterial cell. Many responses have been observed in bacteria that counteract the effects of toxic environmental organic pollutants: saturation-rigidification of cell membrane, cis/trans isomerization of fatty acids, increased content of cyclopropane fatty acids, and changes in branched fatty acids and cardiolipin, production of stress proteins, and elimination of toxic compounds using efflux pump. The study of these mechanisms is the first step in selection of appropriate resistant bacterial strains for bioremediation applications. Next steps should include study of degradation potential and efficacy of the most resistant strains. Setting up suitable experimental systems to examine the cell responses to toxic environmental organic pollutants in the adverse environment and optimal conditions for metabolism of bacterial degraders are important issues in the current bioremediation research agenda.