ONLINE FERMENTATION PROCESS MONITORING OF CARBOHYDRATES AND ETHANOL USING TANGENTIAL FLOW FILTRATION AND COLUMN LIQUID-CHROMATOGRAPHY

This paper describes a fully automated on-line system for the unattended monitoring of bioprocesses. Removal of solids and macromolecules from fermentation broth is achieved with a tangential flow filtration unit (Waters Filter/Acquisition Module). The obtained filtrate is transported in a flow system to a cleanup step, based on solid-phase extraction, followed by introduction into a column liquid chromatographic system. Carbohydrates are then detected by refractive index and ethanol content using a laboratory-made selective amperometric alcohol biosensor. Data acquisition and processing, as well as switching of the system valves, are performed by a computer. The on-line system was used for continuous monitoring of five carbohydrates and ethanol during 24-h ethanol fermentations. Waste water from the Swedish pulp industry was used as the technical substrate. Typical RSD values of the entire setup were on the order of 5-6% over a 24-h period of operation.