Control of glucose feeding using exit gas data and its application to the production of PHB from tapioca hydrolysate byAlcaligenes eutrophus

Summary A method to estimate the glucose concentration in the culture broth using CO₂ evolution rate (CER) data from a mass spectrometer was developed.Alcaligenes eutrophus was cultivated to produce poly(3-hydroxybutyric acid) (PHB) from tapioca hydrolysate using this method. Thek value (g glucose/mol CO₂), defined as the glucose consumption per CO₂ evolution, decreased with culture time and was automatically changed using CER data. The glucose concentration in the culture broth could be controlled at 10 to 20 g/L. A final cell concentration of 106 g/L, PHB concentration of 61 g/L. and PHB content of 58 % of dry cell weight were obtained after 59 h of cultivation.