Characterization of some naphthalene using bacteria isolated from contaminated Cooum Riverine sediment of the Bay of Bengal (India)

Microorganisms capable of using naphthalene as the sole carbon source were isolated from the contaminated sediment of Cooum River. Twenty one isolates were recovered and nine were selected for enrichment due to differences in their morphological characteristics. Out of nine isolates, only four (NS3-SRMND14B, NS14-SRMND14A, NS15-SRMND14D and NS19-SRMND14E) were capable of completely utilizing naphthalene as the sole source of carbon in carbon free minimal medium (CFMM) supplemented with naphthalene. 16S rDNA sequencing showed that all the four isolates were distantly related to each other and belongs to Bacillus sp. (NS3-SRMND14B), Pseudomonas sp. (NS14-SRMND14A), Cellulosimicrobium sp. (NS15-SRMND14D) and Sphingobacterium sp. (NS19-SRMND14E), respectively. Based on the phylogenetic analysis of 16S rDNA sequencing, the isolate Sphingo-bacterium sp. (NS19-SRMND14E) has been identified as novel strain. Polymerase chain reaction (PCR) technique showed the presence of naphthalene dioxygenase (ndo) gene responsible for naphthalene degradation only in the Pseudomonas sp. (NS14-SRMND14A). We observed that the ndo gene is not the only gene responsible for naphthalene degradation. Based on our study, the indigenous microorganisms isolated from Cooum Riverine sediment can be used for bioremediation of the polluted sediment along the Bay of Bengal.