Maximum phenol tolerance and subsequent degradation profile of abacillus pumilus strain mcg 03an isolate from tannery wastewater contaminated soil

The present study emphasizes the phenol hyper tolerance and subsequent degradation behavior of a soil microbial isolate belongs to Bacillus genera. The bacterial species was isolated from tannery wastewater contaminated soil. Amongst the seven different bacterial isolate (MCG 01, 02, 03, 04, 05, 06 and 07), the isolate MCG 03 was selected and used to assess the phenol degradation efficacy at concentrations 500, 1000, 1500 and 2000 ppm. Isolate MCG 03 degrade 1000 ppm phenol within 24 h. Substrate inhibition was realized only at concentration >2000 ppm. The optimum experimental conditions determined were; pH 6.5; temperature 30°C, agitation 150 rpm. The growth kinetics studies revealed that the best fit with a Haldane model with specific growth rate, 0.01 µmax h-1andinhibition constant, KI 629.588 mg L-1 with R2 value of 0.991 compared to Edward model. It has been found that phenol degradation was effected through catechol dioxygenase enzyme system as evidenced through SDS- PAGE electrophoresis and zymogram techniques. Scanning Electron Micrograph displays increase in rod length of MCG 03 at higher concentration of phenol. In conclusion, the strain MCG 03 tolerates at 2000 ppm phenol concentration and suggested the suitability of this strain for bioremediation process.