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

Authors: Samuel E. Agarry, Thomas O.K. Audu, Bamidele O. Solomon

Addresses: Biochemical Engineering Research Unit, Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria. ' Department of Chemical Engineering, University of Benin, Benin-City, Nigeria. ' Biochemical Engineering Research Unit, Department of Chemical Engineering, Obafemi Awolowo University, Ile-ife, Nigeria

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.

Keywords: binary mixed culture; phenol removal; biodegradation; regression modelling; statistical optimisation; process variables; microbial degradation; Pseudomonas aeruginosa; Pseudomonas fluorescens; response surface methodology; RSM; bioremediation.

DOI: 10.1504/IJEP.2010.035921

International Journal of Environment and Pollution, 2010 Vol.43 No.1/2/3, pp.161 - 176

Available online: 09 Oct 2010 *

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