Toxicological evaluation of paper mill sewage sediment treated by indigenous dibenzofuran-degrading Pseudomonas sp.
Organic pollutants present in the pulp and paper mill sewage were extracted with dichloromethane/acetone (1:1v/v), and the extract was added to minimal salt medium to study the degrading and detoxifying potential of Pseudomonas sp. strain ISTDF1. GC-MS analysis performed after biodegradation showed removal of chlorinated compounds like dichloroacetic acid, heptadecyl ester (RT=28.99) and formation of simpler compounds like 4-isopropylbenzaldehyde (RT=7.52). Methyltetrazolium (MTT) assay for cytotoxicity, 7-ethoxyresorufin-O-deethylase (EROD) assay for dioxin-like behaviour and alkaline comet assay for genotoxicity were carried out in human hepato-carcinoma cell line HuH7 before and after bacterial treatment. The bacterium reduced toxicity as shown by a 5-fold increase in LC(50) value, 2110-fold reduction in benzo (α) pyrene equivalent value and an 8-fold reduction in Olive Tail Moment after 240h treatment. The EROD assay was found to be a useful method which indicated positive correlation with MTT and comet assay in post-biodegradation toxicity evaluation.
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067, India. mihirdasjnu@gmail.com
Mihir Tanay
MT
Das
Varaporn
V
Budhraja
Monika
M
Mishra
Indu Shekhar
IS
Thakur
D001572:Benzofurans / Q000378:metabolism*; D002460:Cell Line; D020552:Comet Assay; D008401:Gas Chromatography-Mass Spectrometry; D010209:Paper; D011549:Pseudomonas / Q000378:metabolism*; D012722:Sewage; D013783:Textile Industry; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D001572:Benzofurans; D012722:Sewage; D014874:Water Pollutants, Chemical; C023614:dibenzofuran