On-line state estimation of biomass based on acid production in Zymomonas mobilis cultures

Abstract

The concentrations of biomass, substrate and product are very important state variables of almost every bioprocess and generally unable to be measured directly in␣situ due to the lack of reliable sensors. In this paper, an adaptive observer of the biomass concentration is proposed for an anaerobic fermentation process where only the measurement of the acid product is available on-line. The observer was tested to be effective by several experiments under various operating conditions. In this experimental system, an auto-sampling device was connected between the bioreactor for the fermentation of Zymomonas mobilis and a HPLC so that the concentrations of glucose and ethanol could be directly measured through such implementation.