Optimization of naphthalene biodegradation by a genetic algorithm based response surface methodology

Abstract

Naphthalene biodegradation was studied using the bacterial strain Pseudomonas putida S2. Three medium variables out of seven medium components were selected under Plakett-Burman (PB) design as having significant response on naphthalene biodegradation. These variables were citric acid (additional carbon sources), ammonium sulfate and sodium chloride. The levels of these three variables were optimized by the application of genetic algorithm (GA) based response surface methodology (RSM) in terms of maximum biodegradation efficiency. The maximum biodegradation efficiency of 55.51% was observed at concentrations of 1.0 g L-1, 1.0 g L-1, and 0.7g L -1 for citric acid, ammonium sulfate and sodium chloride, respectively. In addition, the interactive effects of significant medium variables were analyzed using three dimensional surface plots simulated by network output in terms of maximum fitness function.