Phosphatase production by aCitrobactersp. growing in batch cultures retarded by anaerobic or osmotic stress, and the effect of the osmoprotectant glycine betaine

The effect of 500 mM NaCl on the growth, and phosphatase production of a Citrobacter sp. was investigated. Although growth was retarded, phosphatase production was enhanced by 50%. Relief from osmotic stress using the osmoprotectant glycine betaine gave normal growth, but phosphatase activity was reduced. The Citrobacter sp. ceased to grow following a shift to anaerobic conditions, but anaerobically-incubated cells continued to produce phosphatase after a transient lag.