Production of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by Comamonas testosteronii A3

Gerald Renner, Karin Pongratz and Gerhart Braunegg*

Institut für Biotechnologie, Technische Universität Graz, Petersgasse 12, A-8010 Graz, Austria

Article history:
Received May 6, 1996 
Accepted  August 23, 1996

Key words:
polyhydroxyaIkanoate, poly(3-hydroxybutyrate-m-4-hydroxybutyrate), 4-hydroxybutyrate, Comamonas testosteronii

Summary:
The bacterial strain Comamonas testosteronii A3 was investigated for its potential for the production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymers. A screening experiment with accumulation media containing different carbon sources and precursors for 4-hydroxybutyrate production yielded copolymers with mole fractions of 4-hydroxybutyrate above 90%. The medium composition was optimized in shaking-flask experiments for a maximum of polymer production and a maximum of 4-hydroxybutyrate content in the polymer. The kinetics of growth and polyhydroxyalkanoate production were determined in a batch bioprocess. A possible explanation for the production of copolymers with unusually high 4-hydroxybutyrate contents by species from the Comamonas genus is discussed.