On-line culture fluorescence measurement during the batch cultivation of poly-β-hydroxybutyrate producing Alcaligenes eutrophus

Estimation of biomass concentration by on-line fluorimetry was examined during batch cultivations of Alcaligenes eutrophus ATCC 17697, a poly-β-hydroxybutyric acid (PHB) producer. The results obtained revealed a linear correlation between total culture fluorescence and total biomass concentration. The total fluorescence level was attributed to cellular fluorescence and to the fluorescence of compounds presumably produced by the cells and secreted into the culture medium. An increase in the specific cellular fluorescence during the course of the experiments indicated a shift in metabolism that favored the production of PHB.