Abstract
<title>Abstract</title> <p> Oil contamination poses a significant threat to marine ecosystems, with over 2.5 million tons of oil released globally. Despite microbial biodegradation efforts, certain compounds like phenanthrene persist. This study investigates the phenanthrene biodegradation potential of <italic>Cytobacillus horneckiae</italic> S1, isolated from sewage for bioremediation application. Genomic analysis identified thirty phenanthrene degradation genes, including aromatic ring-hydroxylating dioxygenase subunits. Degradation experiments revealed growth coefficients (µ) of 0.09 h-1 and 0.11 h-1 with methanol alone and in a methanol and phenanthrene mixture, respectively. Gene expression analysis indicated upregulation of enzymes associated with meta-cleavage pathways. <italic>Cytobacillus horneckiae</italic> S1 shows promise for phenanthrene bioremediation, assisting with insights into microbial metabolism and bioremediation strategies for contaminated environments. </p>