Abstract: To address polycyclic aromatic hydrocarbons （PAHs） pollution, a naphthalene-degrading bacteria was screened and identified from oil-contaminated soil in Daqing, northern China. Through morphological observation, physiological/biochemical characterization, and 16S rDNA sequence analysis, the strain was identified asBacillus cereusXC-6. The results showed that the strain XC-6 could degrade 1000 mg/L naphthalene, 50 mg/L acenaphthene, 50 mg/L dibenzofuran, 80% fluorene, 30% dibenzothiophene, and 50% phenanthrene within 120 h at 30 ℃. When XC-6 was combined with gold nanoparticles synthesized under aerobic conditions, the naphthalene degradation rate increased by 20% compared to that of bacterial treatment alone, reaching complete degradation within 96 h. By optimizing the culture conditions, it was found that the degradation efficiency of the strain was further improved under suitable temperature, pH and oxygen conditions. This study provided theoretical basis and bacterial resources for the bioremediation of PAH contaminated soil, demonstrating promising application potential. Meanwhile, it established a foundation for investigating nanomaterial-assisted degradation mechanisms and expanding its applications in environmental applications.

Key words: Bacillus cereusXC-6, naphthalene, gold nanoparticles, biodegradation, biohybrid