Isolation and characterization of naphthalene degrading bacteria from soils in warangal.

ABSTRACT

Bacteria capable of utilizing naphthalene, as their sole source of carbon and energy for growth were isolated from three different sites in warangal,Andhra Pradesh. By standard bacteriological methods, these bacteria were characterized taxonomically as belonging to the genus Pseudomonas, Burkholderia or Actinomycetes. Two of the isolates, which showed the highest growth during screening as demonstrated by an increase in their optical densities at 600 nm and named as NITWDBT1 and NITWDBT3.In isolate NITWDBT1, the lowest optimum growth of 0.189 at 600 nm was observed when the level of anthracene was lowest (50 ppm); while the highest optimum growth of 0.578 was recorded when the level of anthracene was highest (300 ppm). Similarly, the lowest optimum growth in isolate NITWDBT3 was 0.173 at anthracene level of 50ppm, while the highest was 0.380 when the level of anthracene was 250 ppm (OD600). These two isolates were identified as Pseudomonas aeruginosa and Burkholderia cepacia respectively, were also able to grow in anthracene and carbazole, but not very much so in 2,4-dichlorophenol and D-camphor. The isolates showed a concentration-dependent growth in all the compounds they were grown. There were visible changes in the colour of the growth medium of the isolates during their incubation, suggesting the production of different metabolites. There were also changes in their medium pH during growth. These studies demonstrate the possession by the bacterial species of novel degradative systems.