The residual refined petroleum products after bacterial degradation was extracted with 15 ml of carbon tetrachloride (CCl4) from the liquid cultures, and analyzed by GC-FID method. The analysis was carried out with a gas chromatograph HP 6890 GC (Hewlett-Packard) equipped with flame-ionization detector (FID). Measurement conditions were as follows: capillary column HP-5 (5% Phenyl Methyl Siloxane), size: 30m x 320μm i.d. x 0.5μm; as carrier gas nitrogen was used at flowing capacity of 30 ml/min; split 1:4; temperature of injector: 280°C, temperature of detector: 310°C; programme of temperature: 80°C (2 min, 12°C/min) to 280°C, 12 min final time).