Accumulation of petroleum hydrocarbon residual considered a major environmental problem in the kingdom of Saudi Arabia cause of intensive efforts for oil detecting. Until now, In situ biodegradation considered the most effective method for petroleum hydrocarbon residual biodegradation. The aim of this study is isolation and identification biodegradable capability bacteria from contaminated sites in Khurais oil field, Dhahran, Saud Arabia via Different morphological and biochemical and molecular methods. Furthermore, degradation level in contaminated liquid medium and soil were evaluated. Three bacterial strains were selected from petroleum-contaminated soils of Khurais oil field depending on their capacity to grow in the existence of hydrocarbon components and identified according to morphological, biochemical. Interestingly, 16S rDNA sequencing fingerprinting results confirmed our bacterial identification as Bacillus subtilis, Pseudomonas aeruginosa and Bacillus cereu. Phyllogenetic tree was constructed and genetic similarity was calculated according to alignments results. Biodegradation patterns for different three isolates were reflected varied degradation ability for three isolates regarding incubation time. Different features were studied for three biodegrading bacterial strains and identified as Bacillus subtilis, Pseudomonas aeruginosa and Bacillus cereus. Remarkable degradation rate % patterns for hydrocarbons residual were recorded for all three isolates with varied.
Keywords: Biochemical tests; Biodegradation; Degradation %; Hydrocarbon components; Khurais oil field; Morphological features; Universal 16S rDNA primers.