Effect of toluene exposure time and concentration on induction of high affinity values for toluene oxidation by bacteria of estuarine seawater samples

Upon amending fresh seawater samples with toluene, metabolism began immediately; autoradiography indicated that a minimum of about 7 % of the bacteria were responsible. Rate of toluene metabolism increased with time, maximal rate of increase occurring about 48 h following exposure. There was no concomitant increase in bacterial populations and, consistent with observations of marine isolates in predator-free systems, the increase in rate was interpreted as induction. Induction followed saturation kinetics as might be expected if the rate of inducer penetration also followed saturation kinetics; Kind observed was the very small value of 1.9 yg 1-l, but was consistent with Michaelis constants for toluene transport observed in other studies.