Simultaneous Biodegradation of Polyaromatic Hydrocarbons by aStenotrophomonassp: Characterization ofnidGenes and Effect of Surfactants on Degradation.
A polyaromatic hydrocarbon degrading bacterium was isolated from a petroleum contaminated site and designated asStenotrophomonassp. strain IITR87. It was found to utilize pyrene, phenanthrene and benzo(a)pyrene as sole carbon source, but not anthracene, chrysene and fluoranthene. Gas chromatography and mass spectroscopy analysis resulted in identification of pyrene metabolites namely monohydroxypyrene, 4-oxa-pyrene-5-one, dimethoxypyrene and monohydroxyphenanthrene. Southern hybridization using naphthalene dioxygenase gene (nidA) as probe against the DNA of strain IITR87 revealed the presence ofnidA gene. PCR analysis suggests dispersed occurrence ofnidgenes in the genome instead of a cluster as reported in a PAH-degradingMycobacterium vanbaaleniiPYR-1. Thenidgenes in strain IITR87, dioxygenase large subunit (nidA), naphthalene dioxygenase small subunit (nidB) and aldehyde dehydrogenase gene (nidD) showed more than 97 % identity to the reportednidgenes fromMycobacterium vanbaaleniiPYR-1. Most significantly, the biodegradation of PAHs was enhanced 25-60 % in the presence of surfactants rhamnolipid and Triton X-100 due to increased solubilization and bioavailability. These results could be useful for the improved biodegradation of high-molecular-weight PAHs in contaminated habitats.
Environmental Biotechnology Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.|Academy of Scientific and Innovative Research, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.
Smita
S
Kumari
Environmental Biotechnology Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.|Department of Biochemistry, Babu Banarsi Das University, Lucknow, 226028 India.
Raj Kumar
RK
Regar
Environmental Biotechnology Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.|Academy of Scientific and Innovative Research, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.|Molecular Biology Laboratory, Department of Zoology, University of Delhi, Delhi, 110007 India.
Abhay
A
Bajaj
Analytical Chemistry Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.
Ratnasekhar
R
Ch
Analytical Chemistry Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.
Gubbala Naga Venkata
GNV
Satyanarayana
Analytical Chemistry Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.
Mohana Krishna Reddy
MKR
Mudiam
Environmental Biotechnology Laboratory, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.|Academy of Scientific and Innovative Research, CSIR-Indian Institute of Toxicology Research, Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226001 India.
Natesan
N
Manickam
Biodegradation; Dioxygenase; Stenotrophomonas; Surfactants