CONTROL OF GLUCOSE FEEDING USING EXIT GAS DATA AND ITS APPLICATION TO THE PRODUCTION OF PHB FROM TAPIOCA HYDROLYSATE BY ALCALIGENES-EUTROPHUS

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. The k 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.