Biodegradation of diesel oil and production of fatty acid esters by a newly isolated Pseudomonas citronellolis KHA

The ability of a newly isolated Pseudomonas citronellolis KHA to degrade diesel oil and to synthesize fatty acid esters has been screened in aerobic batch cultures. The microorganism was able to grow with diesel oil at initial concentrations up to 126 g/l, with optimal growth at 25 g/l. Strain KHA has produced compounds showing strong emulsifying properties (E₂₄ = 75% at the end of the exponential growth phase). The crude extract reduces the surface tension of water from 72 mN m⁻¹ down to 35 mN m⁻¹ with a corresponding minimal concentration value of 60 mg/l. GC and GC–MS analysis of crude product show that the major components are those of hexadecanoic acid propyl ester and octadecanoic acid propyl ester, which have potential for applications in cosmetics, pharmaceutical and foods industries. In addition, strain KHA represents a valuable source of compounds with surface-active properties and potential for the application in clean up of the sites contaminated with hydrocarbons.