OIL BIODEGRADATION BY CONSORTIUM OF OIL DEGRADING MICROORGANISMS IN LABORATORY MODEL SYSTEMS

Abstract. Aim. To evaluate the effectiveness of a consortium of hydrocarbon oxidizing bacteria in various model systems. Methods. Two types of model systems were used for carrying out the experiments: with a liquid mineral medium and with non-sterile soil. To determine the number of microorganisms, a standard method of serial dilutions with seeding to individual colonies was used. Individual strains in the consortium were distinguished using selective media with antibiotics. Oil degradation was assessed by IR spectrometry. Results. The consortium was capable to effective oil destruction in a liquid medium at 4°C and at 24°C, and with respect to control, oil loss is higher at low temperature. At 50°C, the consortium was inactive. In model non-sterile soil systems, the stimulation of native microorganisms by introducing mineral fertilizers did not lead to significant changes in the number of oil-degrading microorganisms but the degree of oil degradation increased. With the joint introduction of the microbial consortium and fertilization, the greatest number of both heterotrophic and oil-degrading strains was observed in the soil system. The degree of oil destruction in this system was also the highest: 59% at 42 days at room temperature. Main conclusions. The developed bacterial consortium has a high oil-degrading activity both at low (4°C) and moderate (18-25°C) temperatures. In non-sterile soil systems, the consortium's microorganisms do not inhibit the local biota, maintaining their numbers at about constant levels, but at the same time they make the main contribution to pollution degradation