ISOLATION AND CHARACTERIZATION OF PHENANTHRENE DEGRADATING BACTERIA FROM DAIRY WASTE SAMPLES

Phenanthrene is the commonly used hazardous chemical in various industries and the detoxification is a big problem till today. In this study, phenanthrene degrading bacteria were isolated from dairy waste samples, characterized by molecular techniques. A total of 10 samples were collected respectively from different spots of dairy industry. Minimum salt agar medium with phenanthrene composition was used to isolate the pure culture of resistant bacterium. Morphological, biochemical tests were done to identify the phenanthrene degrading bacteria. The colonies of the isolates were circular to irregular in dairy samples. Phenanthrene tolerant bacteria were isolated after the dairy waste soil samples was serially diluted and transferred onto M9 minimal agar medium amended with 10mg/l of phenanthrene. A concentration of 10 mg/l was chosen based on the prevailing concentration. Four Phenanthrene tolerant bacteria from dairy waste (HW2, HW1, HW3, HW5) were isolated. From the biochemical and 16srRNA PCR amplification, the bacterium identified was Micrococcus leuteus. The resistance to Phenanthrene by the isolate was tested with various concentrations of Phenanthrene from 0 to 10mM. The Micrococcus luteus showed a MTC value of 28Cfu/ml at 8mM and Bacillus cereus showed least.