Biodegradation kinetics of 2,4,6-trichlorophenol by Rhodococcus rhodochrous in batch culture

Kinetics of biodegradation of 2,4,6-trichlorophenol (TCP) by pure culture of Rhodococcus rhodochrous (DSM 43241) was investigated in batch culture. Batch experiments were performed with different initial TCP concentrations between 50 and 400 mg L−1 at pH 7 and 30 °C in the presence of basal salts medium containing glucose. Percent TCP and toxicity removals decreased with increasing initial TCP concentration due to toxic effects of TCP. The rate and the extent of TCP degradation increased with TCP concentration up to150 mg L−1 indicating no TCP inhibition at low TCP concentrations. TCP concentrations above 150 mg L−1 resulted in decreases both in the rate and extent of TCP degradation due to toxic effects of high TCP contents. The kinetics of TCP biodegradation was modeled by relating the initial TCP degradation rates with the initial TCP concentrations using the non-competitive inhibition model. The kinetic constants were determined by using the experimental data. Percent toxicity removal was also quantified along with TCP removal which decreased with increasing initial TCP concentrations due to toxic effects of TCP.