Degradation of petroleum hydrocarbons with thermotolerant microorganisms

Abstract

In the oil-producing regions of Kazakhstan located in a climatic zone with the predominance of high temperatures, an acute problem of environmental pollution by oil hydrocarbons is noted. This work was aimed at studying the degradation of crude oil by thermotolerant oil-oxidizing strains of microorganisms isolated from the soil in Atyrau region. Oil-oxidizing microorganisms were isolated by the method of cumulative cultures. The destruction of oil was determined using the gravimetric method and gas chromatography with mass spectrometry. The identification of active strains was carried out by sequencing of the 16S rRNA gene. The research results showed that P1-35-14 and P2-50-2 cultures were active at 35°C and 50°C, respectively, while K-3 culture demonstrated high activity at both temperatures. All three strains were the most actively decomposed by n-alkanes of crude oil, such as Tridecane, Dodecane, n-Heptadecane, Pentadecane, Hexadecane, n-Heneicosane, and showed good destruction activity toward aromatic compounds m-Xylene and Naphtalene. According to the results of sequencing the 16S rRNA gene, they were allocated to Rhodococcus fascians K-3, Gordonia amicalis P1-35-14, and Brevibacillus borstelensis P2-50-2 types. These strains are considered to be promising for the biological products development for bioremediation of oil-contaminated soils in an arid climate.