m Khakbaz Varkani - Mahab Ghodss Consulting Engineering Company
f Naeimpoor - Iran University of Science and Technology, Department of Chemical Engineering
fnaeim@iust.ac.ir

Biodegradation of phenol by the bacterial strain Alcaligenes faecalis (ATCC 8750) in mineral salt medium (MSM) was investigated in an external loop airlift bioreactor. Response surface methodology (RSM) based on full factorial design (FFD) was utilized to optimize the initial phenol concentration and air flow rate using Design Expert 6 software. A significant influence of initial phenol concentration on phenol biodegradation time and cell density was noted. The optimum conditions of initial phenol concentration of 1204.40 mg/lit and air flow rate of 3 lit/min was obtained using RSM. Second order polynomial models were developed to quantify the relationships between variables. The applied methodology was validated using further experiments with the specified conditions. In addition, the kinetic behavior of A. faecalis in batch cultures was also investigated over a wide range of initial by using linearized Haldane model. It was clear that the linearized Haldane kinetic model adequately described the dynamic behavior of the phenol biodegradation by the strain of A. faecalis.

Phenol Biodegradation, Alcaligenes Faecalis (ATCC 8750), Airlift Bioreactor, Response Surface Methodology, Optimization