Biodegradation of 2,4-dichlorophenol by Bacillus endophyticus strain: optimization of experimental parameters using response surface methodology and kinetic study

In the present study, the optimization of various experimental parameters, i.e. pH, temperature (degrees C), inoculum size % (v/v) and ammonium sulphate concentration (gL(-1)) at different levels were carried out to enhance the 2,4-dichlorophenol (2,4-DCP) degradation by newly isolated Bacillus endophyticus strain CP1R. The central composite design of response surface methodology (RSM) was applied for the optimization process. It was observed that the maximum biodegradation efficiency of 100% was achieved for 50mgL(-1) 2,4-DCP at optimized condition, i.e. pH 7.36, temperature 35.1 degrees C, inoculum size 10 % (v/v) and (NH4)(2)SO4 concentration 1.4 gL(-1), which was up to 27% higher than that obtained at unoptimized condition. Also the inhibition effect of 2,4-DCP was found to be diminished and degradation capacity of the strain increases significantly. The strain was able to degrade 2,4-DCP efficiently up to 400mgL(-1) with negligible inhibition effect. The biodegradation kinetic of 2,4-DCP at different initial concentration was carried out and the bio-kinetic parameters obtained was R-m=1.53mgDCP h(-1)L(-1) and K-s=711.5 mgL(-1).