Degradation of Carbazole by Novosphingobium sp. Strain NIY3

Abstract

Bacteria were screened to identify strains that could degrade carbazole, a model compound for the N-containing compounds present in fossil fuels which could be removed by biodenitrogenation instead of hydrotreatment. Enrichment cultures from 6 different habitats were examined with carbazole as a source of nitrogen. Bacterium strain NIY3 was isolated, which efficiently metabolized very low concentrations of carbazole. Strain NIY3 is a bright yellow Gram-negative immotile bacterium with a rod shape (0.7×0.7-1.0 μm). DNA base sequence analysis revealed that strain NIY3 belongs to genus Novosphingobium sp., most closely related to Novosphingobium subarcticum (98.3% similarity). Novosphingobium sp. strain NIY3 could degrade 95% of 100 ppm of carbazole in a culture within 3 days.