CALORIMETRIC INVESTIGATIONS OF PHENOL DEGRADATION BY PSEUDOMONAS-PUTIDA

Cyclic and polycyclic aromatic hydrocarbons are among the most widespr ead contaminants in soils, because they are still used in large amount s. Although poisonous to many organisms, consortia of microorganisms o r single species such as Pseudomonas have specialized in the catabolis m of these compounds and use them as their sole energy and carbon sour ce. Phenol, together with some of its catabolic intermediates, and the bacterium Pseudomonas putida were chosen for microcalorimetric invest igations in a batch and a fermentor/flow system. As many of these arom atics are very poisonous, the concentration limits for growth and meta bolism were evaluated optically and calorimetrically, rendering signif icantly prolonged lag-phases at higher concentrations, but no complete inhibition of metabolism. Under such experimental conditions the calo rimetric curves for heat production rate versus time showed reactions following a Michaelis-Menten kinetics in agreement with data from the literature. The calorimetric results proved that phenol is mineralized aerobically to water and carbon dioxide and that an energy balance ca n be established.