OXYGEN-UPTAKE KINETICS OF PSEUDOMONAS-CHLORORAPHIS GROWN IN GLUCOSE-LIMITED OR GLUTAMATE-LIMITED CONTINUOUS CULTURES

Oxygen uptake and glucose and glutamate oxidation kinetics of the hete rotrophic bacterium Pseudomonas chlororaphis grown in glucose- or glut amate-limited cultures under oxygen-saturating or oxygen-limiting cond itions were determined. K-m values for oxygen were 1.4-5.6 mu M Only i n the case of glucose were significantly lower K-m values and enhanced specific oxygen affinity (V-max/K-m) per cell found under oxygen-limi ting conditions. Both K-m and specific affinity values for glucose and glutamate oxidation were apparently affected by oxygen concentration, although a statistically significant enhancement of the oxidation kin etics was found only for glutamate. The kinetic data found for P. chlo roraphis support the conclusion that the outcome of competition for ox ygen with Niti europaea europaea in the rhizosphere of oxygen-releasin g macrophytes will primarily be determined by oxidation kinetics of th e electron donor instead of the oxygen uptake kinetics of the respecti ve organisms.