Carbazole degradation and biosurfactant production by newly isolated Pseudomonas sp. strain GBS.5

A novel biosurfactant producing bacterium, designated as Pseudomonas sp. strain GBS.5, having the ability to degrade carbazole has been isolated. The specific activity of carbazole degradation was found to be 11.36 μmol min−1 g−1 dry cells. GC-MS analysis revealed that the growth of bacterium on carbazole was accompanied with the production of biosurfactant. The biosurfactant produced had the maximum emulsification index of 53 ± 1.52% with n-hexadecane. Sequence analysis of the carbazole degrading genes revealed changes in six different amino acids as compared to other well established strains. Study also confirmed that in addition to carbazole, bacterium has the ability to degrade other polycyclic aromatic hydrocarbons such as fluoranthene, fluorene, naphthalene, phenanthrene and pyrene. A high degradation rate of carbazole and broad substrate range indicates that it has the potential to be used for bioremediation of polycyclic aromatic hydrocarbon contaminated sites.