Biodegradation of pyridine and quinoline by two Pseudomonas strains.

OBJECTIVE To study the degradation of pyridine and quinoline by two Pseudomonas. METHODS Based on the analysis of 16S rRNA gene sequence homology and the intergenic spacer region sequence, the two isolates were identified. The degradation capability of pyridine and quinoline was determined according to spectrophotometry and Electrospray Ionisation/Mass Spectrometry (ESI/MS). The degrading plasmids were detected by plasmid curing and the possible degrading genes were also cloned. RESULTS The two isolates were identified as Pseudomonas and nominated XJUHX-1 and XJUHX-12. The two Pseudomonas were tolerant with pyridine and quinoline and two and four possible metabolites were detected in the culture medium containing quinoline and pyridine, respectively. The degrading capability of curing plasmids was lower than the crude isolates. The gene segments coding for the NADH (acceptor) reductase component OxoR for quinoline degradation and nitrogenase reductase (NifH) of denitrification for pyridine degradation were amplified from the genome of XJUHX-1 and XJUHX-12, both were cloned and expressed in E. coli BL 21 producing recombinant proteins with molecular mass of 43 kDa and 16 kDa. CONCLUSION The two isolates could degrade pyridine and quinoline respectively.