The Isolation & Characterization of Several Strains of Naphthalene Degrading Bacteria obtained from oil-contaminated sites

Abstract

Naphthalene is the simplest example of a PAH. PAHs occur in oil, coal, and tar deposits, and are produced as byproducts of fuel burning (whether fossil fuel or biomass). Common naphthalene degrading bacteria include Pseudomonas spp., Vibrio spp., Mycobacterium spp., Staphylococcus spp., and Sphingomonas spp. A well studied example of naphthalene catabolism is the naphthalene degradation (nah) pathway of Pseudomonas putida NCIB 98164. Five different isolates have been isolated which are Gram +ve bacteria and they all are naphthalene degrading by nature. It has been concluded that the bacterial strain capable of utilizing naphthalene is able to degrade it in 6 days. From HPLC analysis it is concluded that the concentration of naphthalene decreases as compared from blank solution which do not contain bacteria. HPLC analysis reveals that bacteria catabolises naphthalene within 6 days and decreases its absorbance due to less number of naphthalene present in the solution. Screening for relatively fast-growing naphthalene-degrading bacteria from different sites which were contaminated with crude oil resulted in the recovery of three isolates B. naphthovorans strain MN-003, Staphylococcus sp. strain MN-005 and Micrococcus sp. strain MN-006. Although the isolation methods were unbiased and could select for both Gram-positive and Gram-negative bacteria, all three candidate strains were Gram-positive. This dominance of Gram-positive bacteria is demonstrated in the high relative abundances of B.naphthovorans strain MN-003, Staphylococcus sp. strain MN-005 and Micrococcus sp. strain MN-006 in the enrichment culture.