Degradation of oil and oil products by microorganisms isolated from the Azerbaijani coast of the Caspian Sea at low temperatures

Abstract

The object of the study is microorganisms isolated from the Azerbaijani territory of the Caspian Sea, capable of decomposing oil and oil products at low temperatures of 4–6 °C. The purpose of this work was to study bacteria and fungi capable of actively assimilating oil, gasoline, kerosene, diesel fuel at a temperature of 4–6 °C in order to solve the problem of environmental pollution in this region. The studied most effective biodestructors are combined into associations that can be used to create an active biological product based on native microorganisms with its further use for water bioremediation, as well as treatment of tanks and other containers used for long-term storage of petroleum products at a temperature of 4–6 °C. The process of degradation of samples of used oils at the molecular level of the selected compounds was studied by reverse-phase high-performance liquid chromatography. As a result of chromatographic and spectroscopic studies, it was found that almost all microorganisms decompose the tested oil products. Only weak peaks remained on the chromatogram, which is a clear indicator of the deep biodegradation carried out by these microorganisms. Thanks to the chromatographic and spectral analysis of oil and products of its decomposition, an oxidation sequence has been established, indicating the decomposition of the last aromatic fraction. As a result, a general picture was obtained on the amount of degradation products containing carboxyl, keto-, hydroxyl groups, which is not enough to determine the processes of transformation of initial products into final ones. All this testifies to the multidirectionality of biodegradation processes