Treatment of wastewater containing high concentrations of terephthalic acid by Comamonas sp. and Rhodococcus sp.: kinetic and stoichiometric characterization

In this work, terephthalic acid degradation was studied with two strains that were isolated and identified as closely related to Comamonas (99%) and Rhodococcus (99%) genus. A characterization of both strains was carried out during batch experiments performed at two oxygen transfer capacities (0.094 +/- 0.011 and 0.538 +/- 0.042 g O-2/L/h) and five concentrations of terephthalic acid (2.5 to 15.0 g/L). Maximum degradation rates of 0.073 +/- 0.004 and 0.062 +/- 0.003 g TOC/L/h, were observed, for Comamonas sp. and Rhodococcus sp., respectively. However, a degradation rate of 0.159 +/- 0.011 g TOC/L/h was reached with a mixed culture. Haldane, Aiba, Edwards and Andrews models were used to fit terephthalic acid degradation kinetics, being Haldane the model that best fitted the results. Several parameters were determined including, maximum growth rate, growth yield, substrate affinity and inhibition constant.