The microbial degradation of phenol by pure culture of Candida tropicalis SSK01 cells isolated from petroleum contaminated soil is studied in batch mode. Response surface methodology was used to optimize the medium composition for phenol degradation. Initial screening of variables such as initial phenol concentration, NH4NO3, KH2PO4, CaCl2 ,K2HPO4, MgSO4, KCl and Yeast extract was done by using Plackett–Burman experimental design .It was found that initial phenol concentration (p=0.016), NH4NO3 (p<0.011), CaCl2 (p<0.018), KH2PO4 (p<0.018) and Yeast Extract (p<0.047) had a significant effect on phenol degradation. Then Central Composite Design was employed to determine optimal concentration of each significant variable. Based on CCD the optimum concentrations of the critical components were found to be initial phenol concentration 600 g/l, NH4NO3-2.5 g/l , CaCl2-0.015 g/l ,KH2PO4-0.75 g/l and Yeast Extract -0.07 g/l for 98.5 % phenol degradation in 72 hours. The R2, adjusted R2 and Predicted R2 values calculated by CCD were 0.9965, 0.944 and 0.99860 showed that experimental values are in good agreement with predicted values.
Phenol degradation, Candida tropicalis SSK01, Medium optimization
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