Biodegradation of Petroleum Hydrocarbons by Pseudomonas putida Strain MHF 7109

Pseudomonas putida MHF 7109 has been isolated and identified from cow dung microbial consortium for biodegradation of selected petroleum hydrocarbon compounds – benzene, toluene, and o‐xylene (BTX). Each compound was applied separately at concentrations of 50, 100, 250, and 500 mg L^?1 in minimal salt medium to evaluate degradation activity of the identified microbial strain. The results indicated that the strain used has high potential to degrade BTX at a concentration of 50 mg L^?1 within a period of 48, 96, and 168 h, respectively; whereas the concentration of 100 mg L^?1 of benzene and toluene was found to be completely degraded within 120 and 168 h, respectively. Sixty‐two percent of o‐xylene were degraded within 168 h at the 100 mg L^?1 concentration level. The maximum degradation rates for BTX were 1.35, 1.04, and 0.51 mg L^?1 h^?1, respectively. At higher concentrations (250 and 500 mg L^?1) BTX inhibited the activity of microorganisms. The mass spectrometry analysis identified the intermediates as catechol, 2‐hydroxymuconic semialdehyde, 3‐methylcatechol, cis‐2‐hydroxypenta‐2,4‐dienoate, 2‐methylbenzyl alcohol, and 1,2‐dihydroxy‐6‐methylcyclohexa‐3,5‐dienecarboxylate, for BTX, respectively. P. putida MHF 7109 has been found to have high potential for biodegradation of volatile petroleum hydrocarbons.