BIODEGRADATION OF PCB CONGENER (2, 4 DICHLOROBIPHENYL) BY MICROCOCCUS SP. ISOLATED FROM TRANSFORMER OIL CONTAMINATED SOIL
Shobha K. Jayanna, Kushalatha M.*, Murulidhar Nayak M. and Goutham S. A.
ABSTRACT
The bacterium was isolated from transformer contaminated soil and was identified as Micrococcous sp. based on their biochemical characteristics. The 0.2% of 2,4-Dichloro biphenyl (2,4- DCB ) was included in the growth medium of isolated bacterium as carbon source to study its biodegradation potential. The growth of the bacterium was monitored turbidometrically by reading absorbance at 660nm. The appearance of yellow metabolite, 2-hydroxy-6-oxo-6-phenyl-hexa-2,4-dienoic acid (HOPDA), during the growth of Micrococcus sp. on2,4- DCB as a substrate, showed maximum absorption at 398nm with no significant chloride release. The degradation study was monitored by GC-MS analysis; GC-MS of control 2,4 DCB with retention time 15.712min was compared to Ionization mass spectra fragmentation pattern stored in computer library ofNIST-MS Type Version -2, 2008. GC-MS of ethyl acetate extract of spent medium showed 91% reduction of 2,4- DCB with chlorobenzoic acid as one of the major intermediary metaboliteand was identical to the GC-MSof chlorobenzoic acid as per computer library of NIST-MS Type Version -2, 2005. The reduction in the substrate concentration was calculated as percentage of degradation by determining the net decrease in Electron capture detection.
Keywords: 2,4- dichloro biphenyl; Micrococcous sp,; GC-MS; 2-hydroxy-6-oxo-6phenyl-hexa-2, 4-dienoic acid; chlorobenzoic acid.
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