Delafield, F. P. (University of California, Berkeley), M. Doudoroff, N. J. Palleroni, C. J. Lusty, and R. Contopoulos. Decomposition of poly-beta-hydroxybutyrate by pseudomonads. J. Bacteriol. 90:1455-1466. 1965.-A number of aerobic pseudomonads capable of using poly-beta-hydroxybutyrate as sole source of carbon have been partially characterized. One was selected for special study and described as a new species, Pseudomonas lemoignei Delafield. This bacterium constitutively produces extracellular digestive enzymes that hydrolyze the polymer to a mixture of d-beta-hydroxybutyrate and the dimeric ester of this acid, as well as an intracellular "dimer hydrolase" which hydrolyzes the dimeric ester. The exoenzymes are excreted during growth, but mainly at its cessation. Metabolism of beta-hydroxybutyrate largely suppresses enzyme excretion and causes a disappearance of excreted enzyme.