Logical and experimental design for phenol degradation using immobilized Acinetobacter sp. culture

Phenol and phenolic compounds cause severe pollutant to the nature. Phenol degradation using microbes has been attracted the attention of many researchers. In this study Plackett-Burman design has been used to map and optimize the points affect in the degradation process. Nine variables include pH (X1), oC (X2), glucose (X3), yeast extract (X4), meat extract (X5), NH4NO3 (X6), K-salt (X7), Mg-salt (X8) and trace elements (X9) as a media constituents are optimized during the phenol degradation process using immobilized Acinetobacter sp. According to Plackett-Burman design experiments the maximum degradation rate was 31.25 mg/l/h. Logical and statistical analysis of the data lead to select pH, Temperature and Meat extract as the most important three factors affecting on the phenol degradation rate. These three variables have been used in Box-Behnken experimental design, which result in degradation rate equal to 35.7 mg/L/hr. Microsoft Excel 2002 solver tool was used to optimize the model created from Box-Behnken. The calculated degradation rate was 37.30 mg/l/hr while the experimental degradation rate was 38.45 mg/L/hr, which prove the model accuracy. The use of logical analyses of the data covers the limitation of the statistical methods in selecting the correct variables. We recommended using logical and statistical data analysis for optimization the phenol degradation rate and other related processes