Rate of Biodegradation of Phenol by<i>Klebsiella oxytoca</i>in Minimal Medium and Nutrient Broth Conditions

Abstract

ABSTRACT The rate of biodegradation of phenol by Klebsiella oxytoca strain was studied in the nutrient broth and M9 minimal medium. It was found that K. oxytoca degrade phenol at elevated phenol concentration where 75% of initial phenol concentration of 100 ppm will degrade within 72 h. This rate was increased with increasing the initial cell densities, increasing the aeration rate and increasing the time required for complete degradation. At phenol concentration above 400 ppm, the cells were unable to degrade the substrate efficiently due to the increasing concentration of phenol in the medium. The culture conditions were also showed a significant impact on the ability of these cells to remove phenol. The optimum solution pH and temperature were 6.8 and 37°C, respectively. The growth of these cells in the presence and absence of phenol was modeled and it was found that the Recatti equation best fit the growth in the absence of phenol whereas the Voltera equation accounted for the history of the cell population in the presence of phenol.