A rapid gas chromatographic method for the determination of poly-?-hydroxybutyric acid in microbial biomass

The gas chromatographic method for the determination of poly-β-hydroxybutyric acid (PHB) consists of a mild acid or alkaline methanolysis of poly-β-hydroxybutyric acid directly without previous extraction of PHB from the cells; this is followed by gas chromatography of the 3-hydroxybutyric acid methylester. The method is characterized by high accuracy and excellent reproducibility, permitting determinations as low as 10−5 g/l. Only 4 h is required from sampling from the fermenter till completion of the PHB determination.