D.C. Mosteller, C.E. Larkin II and K.F. Reardon¹

Department of Chemical and Bioresource Engineering, Colorado State University, Fort Collins, CO, 80523-1370, 970-491-6505, E-MAIL ¹


Contamination of ground water and soil is most often a mixture of pollutants, yet most quantitative studies of biodegradation either focus on one compound or describe the mixture as a single concentration (e.g., TOC). Information can be obtained from these approaches but they do not allow prediction of the fate of a single pollutant in the mixture or extrapolation of results to different mixtures.

As an initial step in the study of the biodegradation of organic pollutant mixtures, the biodegradation of benzene, toluene and phenol by Pseudomonas putida F1 has been measured and modeled. Each of these compounds can serve as the sole source of carbon and energy for this microorganism, and the initial step in the metabolism of each is catalyzed by toluene dioxygenase. Batch cultivation experiments were performed and the measurements of cell and pollutant concentration used to test different models of mixed pollutant biodegradation. In addition, toxicity tests have been conducted to verify the effectiveness of biodegradation. Experiments are currently underway to measure levels of toluene dioxygenase activity during biodegradation of different mixtures with the goal of relating these levels to the pollutant removal rates.


biodegradation, mixtures, kinetics, toluene dioxygenase

This paper is from the Proceedings of the 10th Annual Conference on Hazardous Waste Research 1995, published in hard copy and on the Web by the Great Plains/Rocky Mountain Hazardous Substance Research Center.