Substrate inhibition kinetics: Naphthalene degradation by Pseudomonas putida

A BSTRACT Biodegradation of naphthalene by Pseudomonas putida was studied in this article. The influence of pH, glucose concentration and inoculum concentrations on the growth and subsequent naphthalene degradation potential of P. putida were investigated. The naphthalene degradation and microbial growth was higher at optimum pH (pH 7), glucose concentration (500 mg/L) and inoculum concentration (3%). The non-ionic surfactants were used in the case of very high concentrations of naphthalene (500-2500 mg/L) to investigate the maximum naphthalene tolerance potential of P. putida. The surfactants used were Triton X-100 and Tween-80. These surfactants enhanced the availability of naphthalene to the microbes. Results indicated that naphthalene was completely degraded by P. putida at an initial naphthalene concentration of 500 mg/L. Further increase in naphthalene concentration decreases the degradation potential of P. putida. The inhibition characteristics of substrate were described using four kinetics models (Haldane, Webb, Edward and Aiba). These kinetics models fitted very well and effectively describe the dynamic behavior of naphthalene biodegradation by P. putida