Growth and phosphate uptake of a high phosphate accumulating bacterium, Arthrobacter globiformis PAB-6 in continuous culture

A high phosphate accumulating bacterium, Arthrobacter globiformis PAB-6, was grown in a chemostat under glucose-limitation. Two different growth patterns at steady state with various dilution rates were obtained. In one case, cells having a coccus shape tended to washout at a low dilution rate, 0.2 (h(-1)). In another, cells with a rod shape grew faster and gave a good steady-state growth at a dilution rate of 0.4. Such a close relationship between growth rate and cell morphology was found both in continuous and batch cultures. The amount of phosphate uptake per cell mass was almost constant irrespective of the dilution rate, but the rate of the uptake was maximum at about the dilution rate of 0.4. A clone of PAB-6 was isolated from the continuous culture with high dilution rate and had maximum specific growth rate of 0.7 in a simple glucosesalt medium.