ONLINE AND IN-SITU MONITORING TECHNOLOGY FOR CELL-DENSITY MEASUREMENTIN MICROBIAL AND ANIMAL-CELL CULTURES

Commercially available on-line and in-situ devices for monitoring cell density are reviewed in this article. Principles of operation are des cribed as well as capabilities of these probes in specific measurement applications based on literature reports. Pilot-scale experimental ob servations from three optical density probes, the Cerex, Monitek and W edgewood designs, have been included for Escherichia coli fermentation s. Requirements for future on-line and in-situ instruments are discuss ed as well as the impact of current imitations on widespread applicati on.