Fig. 3
From: Feedback control based on NADH fluorescence intensity for Saccharomyces cerevisiae cultivations
a Evolution of the dissolved oxygen and the NADH intensity during the fed-batch operation with the closed-loop control. b Evolution of the NADH intensity and its derivative as a metabolic signal during the fed-batch operation with the closed-loop control. The arrows show the points that the upper threshold was reached, but it might be because of the noise of the NADH intensity. c Metabolic signals and the feed rate profile during the controlled feeding phase. The arrows refer to the time that the lower threshold signal was not reached. d Glucose, ethanol, and biomass concentrations during the fed-batch operation with the closed-loop control