Abstract: Polycyclic Aromatic Hydrocarbons (PAHs) are persistent hydrophobic organic
pollutants ubiquitously found in the environment. PAHs consist of cytotoxic,
mutagenic and carcinogenic properties and causes serious hazard to human health
and environment. Hence, in this investigation eight phenanthrene (250 mg L-1)
degrading bacterial strains were isolated by enrichment method from petroleum
contaminated sludge samples. Among these isolates, one efficient degrading strain
was identified and characterized by using morphological, biochemical, chemotaxonomic
(FAMEs analysis) and molecular (16S rDNA sequencing) methods. Based on these
studies the strain was identified as gram positive, motile, spore forming, pink
pigmented cocci with oxidase negative reaction and utilized sugars such as arabinose,
xylose and rhamnose as carbon source. It is susceptible to kanamycin, nalidixic
acid and novobiocin type of antibiotics. The dominant fatty acids found in this
strain are 15:0 anteiso (44.16%), 15:0 iso (26.36%). Phylogenetic analysis of
this strain showed 99% sequence similarity with Kocuria rosea and the
strain name as PDM-7 was adopted. The degradation study illustrates that this
strain utilizing about 82% of phenanthrene in six days. Therefore, this strain
can be efficiently used for the bioremediation of PAHs contaminated marine environments
and soils. |