Biodegradation of phenanthrene by piezotolerant Bacillus subtilis EB1 and genomic insights for bioremediation

A marine strain B. subtilis EB1, isolated from Equator water, showed excellent degradation towards a wide range of hydrocarbons. Degradation studies revealed dense growth with 93 % and 83 % removal of phenanthrene within 72 h at 0.1 and 20 MPa, respectively. The identification of phenanthrene degradation metabolites by GC-MS combined with its whole genome analysis provided the pathway involved in the degradation process. Whole genome sequencing indicated a genome size of 3,983,989 bp with 4331 annotated genes. The genome provided the genetic compartments, which includes monooxygenase, dioxygenase, dehydrogenase, biosurfactant synthesis catabolic genes for the biodegradation of aromatic compounds. Detailed COG and KEGG pathway analysis confirmed the genes involved in the oxygenation reaction of hydrocarbons, piezotolerance, siderophores, chemotaxis and transporter systems which were specific to adaptation for survival in extreme marine habitat. The results of this study will be a key to design an optimal bioremediation strategy for oil contaminated extreme marine environment.