INCORPORATION OF 2-METHYL-3-HYDROXYBUTYRIC ACID INTO POLYHYDROXYALKANOIC ACIDS BY AXENIC CULTURES IN DEFINED MEDIA

Alcaligenes eutrophus and Burkholderia cepacia synthesized and accumul ated a terpolyester consisting of 3-hydroxybutyric acid, 3-hydroxyvale ric acid, and 2-methyl-3-hydroxybutyric acid (2Me3HB) if the cells wer e cultivated in a mineral salts medium containing tiglic acid as the s ole carbon source or in combination with gluconic acid. The presence o f 1-2 mol% of 2Me3HB in the polyester was confirmed by comparison with chemically synthesized methyl ester of 2Me3HB and by nuclear magnetic resonance spectrometry as well as by gas chromatography/mass spectrom etry. This is the first report of the incorporation of 2Me3HB by axeni c cultures cultivated under defined conditions.