Homenko L. Noсardioform aсtinobaсteria are destructors of motor oils

The ability of nocardioform actinobacteria belongongin to genera Dietzia, Gordonia and Rhodococcus to degrade mineral motor oils of the class 15W-40 of 5 different brands has been determined. The strains of G.rubripertincta UCM Ac-179, R.erythropolis UCM Ac-50 and D.maris UCM Ac-205 possessed the highest degrading activity of the given oils. It has been shown that concentration of zinc dithiophosphate in oils and additives determined sensitivity of actinobacteria to high levels of these compounds. Among heavy metal ions present in motor oils copper, aluminum and zinc were most toxic to the studied strains. Most strains degrading motor oils maintain viability under a broad range of pH (6 - 10), temperature (5 - 42°С) and NaCl concentration (1-7 %), heating at 60°С for 15 minutes and were resistant to sulfur at concentration 0.2-4.0 mg/ml and phenol at 5-10 mg/ml. It has been shown that during assimilation of motor oil hydrocarbons the cell surface hydrophobicity and synthesis of cell-bound surface-active substances considerably increased. These substances are emulsifying agents (Е24 = 40,3 - 57,3 %) and form stable oil-water emulsions. Glycolipids (trehalose mono- and dimycolates) made up the major part of these substances and decrease water surface tension to 45,3-35,0 mН/m. The studied strains have been found to remove motor oil traces from the surface of plastic jerricans. The selected active strain-destructors of motor oils have a potential use in bioremediation of motor oil-contaminated natural environments.