Abstract

Azotobacter species-An efficient napthalene degrader

Author(s): K.G.Maske, T.A.Kadam, A.A.Atnoorkar

Many polycyclic aromatic hydrocarbons (PAHs) are known to be toxic and their contamination of soil and aquifers is of great environment concern. In the present study the degradation of naphthalene a model PAH by nitrogen fixing bacteria was investigated and an efficient naphthalene degrader sp. was screened. Twenty isolates degrading naphthalene as a sole source of carbon and energy were isolated from petroleum contaminated sites. They were identified by using standard microbiological methods. Isolates were screened on the basis of growth in terms of O.D. at 610 nm, CFU mL-1 and degradation efficiency. Screened isolates were– Azotobacter chroococcum and Azotobacter vinelandii, confirmed bymolecular identification using 16 S r RNAgene analysis .They showed 0.28, 0.22, O.D. at 610 nmrespectively at 1 m mol concentration of naphthalene after 72 hr. of incubation. HPLC analysis of diethyl ether extract obtained from cultures of Azotobacter chroococcum, Azotobacter vinelandii showed 98%, 97.7%, degradation of naphthalene respectively at the end of 72 h. HPLC elution profile of extract indicated presence of intermediate metabolites of Napthalene degradation at different retention time.