Environmental pollution by petroleum hydrocarbons is one of the significant concerns of the contemporary world. This study aimed to evaluate the enhancement of petroleum oil biodegradation using biosynthetic nanoparticles. Seventeen petroleum-degrading bacteria were isolated from an oil-polluted water samples in Alexandria, Egypt, by the Oil Refinery Company. The magnetic nanoparticles were biosynthesized by different bacterial isolates and the selection of the highest nanoparticles producer was investigated. The biosynthesis of nanoparticles and their role in the biodegradation process was determined. However, one bacterial species showed the highest production of nanoparticles. The synthesized nanoparticles were then analyzed using the dynamic light scattering technique (DLS) to determine the size of nanoparticles which was found to be 71.21nm. This isolate was identified by 16S rRNA gene sequence analysis into Pseudomonas aeruginosa ATCC 10145with a similarity of 99.53 %. Pure and bacterial consortium were utilized to study the bioremediation process with/without bio-nanoparticles. The oil remaining after bioremediation was extracted. After 14 days of incubation, the maximum degradation of crude oil was found to be 96.7 % with mixture of bacterial isolates was determined by GC analysis without bio-nanoparticles. The nanoparticles catalyst increases the microbiological reaction rates by stimulating the activity of microbes during the biodegradation process. The percentage biodegradation was increased with bacterial consortium and magnetic bio-nanoparticles to reach 98.9% after 7 days of incubation. With this excellent biodegradation efficiency, we believe that the bacterial consortium with bio-nanoparticles entails high potential treatment for industrial applications for the biodegradation of oil-contaminated sites.