biochemical, molecular and ecological characterization of petroleum biodegradable bacteria in misan province/iraq

Oil-biodegradable bacterial strains were isolated, identified and characterized from oil contaminated soil samples from three oil refineries in misan province. four bacterial isolates were characterized at biochemical levels by ordinary and standard bacteriological tests. the isolates were further identified by the vitek-2 system. three bacterial isolates (sphingomonas paucimobilis, novosphingobium subterraneum and bacillus subtilis) were identified by universal primers and one bacterial isolate (pseudomonas putida) by pseudomonas sp. primer. the four bacterial isolates were grown on mineral salt media (msm) supplemented with 0.5% crude oil and incubated at three incubation periods (7, 14 and 21) days were showed positive biodegradation of crude oil. the results revealed that the higher percentageof the degradation rate of n-alkanes by pseudomonas putida (84.21%) followed by bacillus subtilis (83.39%), sphingomonas paucimobilis (79.63%) and novosphingobium subterraneum (78.18%), while the higher percentage of the degradation rate of pahs occurred by sphingomonas paucimobilis (93.39%) followed by novosphingobium subterraneum (92%), pseudomonas putida (88. 84%) and bacillus subtilis (85.99%) at the end of the incubation periods (21 days).