Abstract
A facultative anaerobic bacterium Pseudomonas nitroreducens (D-3) isolated in the presence of naphthalene and pyrrolidine as the sole carbon and energy source from soil sample obtained from cashew nut food processing industry. On the basis of phenotypic and phylogenetic characteristics, it was identified as a member of the genus Pseudomonas with 100% sequence similarity to P. nitroreducens. The degradation efficiencies of naphthalene and pyrrolidine were examined by GC-MS revealed that the isolate was able to remove above 90% after 144 h at 37 degrees C. Under anaerobic conditions, degradation of pyrrolidine was coupled with a respiratory nitrate reduction. The strain was also able to degrade phenanthrene, petrol, diesel, diesel oil, kerosene, anthracene, pyridine, xylene and toluene. The pathway of naphthalene degradation was explored through analyzing the intermediary metabolites. Results revealed that the carboxylation process of napthalene produced 1, 2, 3, 4-tetrahydro-1-carboxynapthalene; decarboxylation leads to the formation of catechol, and carbon backbone rearrangements lead to beta-oxidation reaction. This study demonstrated that under anaerobic condition, naphthalene, pyrrolidine, phenanthrene and other hydrocarbons were effectively biotransformed by indigenous denitrifying bacteria.