Abstract

The biodegradation potential of an indigenous monoculture of Pseudomonas aeruginosa was studied in batch fermentation using synthetic phenol in water in the concentration range of (100 - 500) mg/L as a model limiting substrate. The effect of initial phenol concentration on the degradation process was investigated. Phenol was completely degraded at different cultivation times for various initial phenol concentrations. Increasing the initial phenol concentration from 100 to 500 mg/L, increased the lag phase from 0 to 24 h and correspondingly prolonged the degradation process from 54 to 168 h. This implies that there was decrease in biodegradation rate as initial phenol concentration increased. Four substrate utilization models were examined, and out of these, the adapted Miura model was found to be the best fit for description of kinetics. The r_smax decreased and K_s increased with higher concentration of phenol. The r_smax has been found to be a strong function of initial phenol concentration. The bacterial culture followed substrate inhibition kinetics and the specific phenol consumption rates were fitted to five inhibition models. The Haldane and Yano and Koga inhibition models were found to give the best fit. Therefore, the biokinetic constants estimated using these models show good potential of the monoculture of Pseudomonas aeruginosa and the possibility of using it in bioremediation of phenolic waste effluents.