Microbial degradation of petroleum hydrocarbons is one of the major practices in the natural decontamination process. We tested the effectiveness of some carriers and immobilization methodology for four cultures of hydrocarbon-degrading strains isolated from oil-polluted wastewater of the American Petroleum Institute (API) separators (1, 2, and 4) of the Alexandria Petroleum Company (APC), Alexandria, Egypt. Adsorbing cells on a sponge gave optimal total petroleum hydrocarbon removal efficiency for the four cultures in comparison to free cells. Comparing a designed bacterial consortium with individual cultures revealed that the highest crude oil degradation percentage was recorded by mixed culture (81.70% removal efficiency) 1.083 times higher than that obtained from Bacillus brevis (75.42 %). The use of a fixedbed bioreactor for biodegradation of crude oil by bacterial cultures held on sponge cubes showed that the highest crude oil degradation percentage was recorded by mixed culture (87.53%), followed by individual cultures of Pseudomonas aeruginosa KH6 (82.97%), providing insight for biodegradation by immobilized bacterial consortia within bioreactors. Significant degradation in both aliphatic and aromatic hydrocarbons, analyzed by GC/MS, was obtained from mixed culture adsorbed on sponge. Simulation strategy was applied for oily wastewater sample, recommending the combination of biostimulation and bioaugmentation techniques, which achieved 92.17% and 91.30% removal efficiencies in a bioreactor packed with sponge or polyethylene, respectively. Therefore, the tested strains could be utilized for industrial effluent treatment and decontamination of natural polluted areas and could be reported in future correspondence.