Indirect estimation of poly-β-hydroxybutyric acid by cell carbon analysis

Nitrogen-limited batch cultures of Alcaligenes eutrophus were characterised by two phases: an exponential growth phase followed by a PHB accumulation phase where the increase in cell carbon concentration was caused exclusively by PHB accumulation. Consequently, the PHB concentration could be estimated indirectly by cell carbon analysis. The conventional spectrophotometric method for PHB estimation and the method described in this paper gave identical results. However, our method is more rapid and requires smaller sample volumes.