Diversity of 4-Chloro-2-nitrophenol-Degrading Bacteria in a Waste Water Sample

Abstract

Eighteen bacterial strains, isolated from a waste water sample collected from a chemically contaminated site, Patancheru (17°32′N 78°16′E/17.53°N 78.27°E), India, were able to decolorize 4-chloro-2-nitrophenol (4C2NP) in the presence of an additional carbon source. These eighteen 4C2NP-decolorizing strains have been identified as members of four different genera, includingBacillus,Paenibacillus,Pseudomonas, andLeuconostocbased on the 16S rRNA gene sequencing and phylogenetic analysis. Most of the bacteria (10) belonged to the genusBacillusand contributed 56% of the total 4C2NP-degrading bacteria, whereas the members of generaPaenibacillusandPseudomonasrepresented 22% and 17%, respectively, of total 4C2NP-degrading isolates. There was only one species ofLeuconostoccapable of degrading 4C2NP. This is the first report of the diversity of 4C2NP-decolorizing bacteria in a waste water sample. Furthermore, one bacterium,Bacillus aryabhattaistrain PC-7, was able to decolorize 4C2NP up to a concentration of 2.0 mM. Gas chromatography-mass spectrometry analysis identified 5-chloro-2-methylbenzoxazole as the final product of 4C2NP decolorization in strain PC-7.