Bioremediation of land oil spills: diversity of microorganisms degrading oil hydrocarbons

Environmental pollution by petroleum is an increasing global problem. In Russia this environmental problem is of such a large scale that it renders the excavation and off-site treatment of oil-contaminated soils and industrial wastes hardly possible. Therefore, in situ methods are attractive alternative. Bioremediation is a cost-effective and contaminant-specific approach. At the Institute of Biochemistry and Physiology of Microorganisms (Pushchino, Russia) there is a large collection of microorganisms degrading oil products. Their survival, stability, competitiveness, biodegradative activity, and efficiency under varying conditions have been investigated. Polycyclic aromatic hydrocarbons (PAH) belong to a recalcitrant group of environmental pollutants, They are components of oil and often occur in industrial wastes, The biochemical pathways of PAH catabolism and their genetic control in different strains were studied. It was shown that different combinations of host bacteria and plasmids changed growth characteristics and competitiveness of Pseudomonas strains. The transfer of degradative plasmids may enhance the biodegradative potential of indigenous microorganisms. Model systems were elaborated to determine the efficiency of PAH degradation [1], All these approaches can be used for the development of biotechnologies for cleanup of oil-contaminated soils.