Optimisation of process variables for microbial degradation of phenol by binary mixed culture of Pseudomonas aeruginosa and Pseudomonas fluorescens using response surface methodology

Abstract

The removal efficiency of phenol from aqueous solutions was measured using an indigenous freely suspended binary mixed culture of Pseudomonas aeruginosa and Pseudomonas fluorescens. Experiments were performed as a function of temperature (25?45°C), aeration (1.0?3.5 vvm) and agitation (200?600 rpm). Optimisation of these three process parameters for phenol biodegradation was studied. Statistically designed experiments using response surface methodology were used to get more information about the significant effects and the interactions between the three parameters. A 2³ full-factorial central composite design followed by multistage Monte Carlo optimisation technique was employed for experimental design and analysis of the results. The optimum process conditions of temperature 30°C, aeration 3.0 vvm and agitation 300 rpm were recognised for maximising phenol degradation (removal). Maximum removal efficiency of phenol was achieved (100%) at the optimum process conditions.