On-line Measurement of Viable Biomass

Abstract

Bioprocesses are in general not very well controlled. This is particularly the case when people are interested in the on-line control of biomass. This chapter discusses an instrument called the biomass monitor (BM), which uses a capacitance measurement and can be used for online measurement of any cell type. Results from a brewing company show very little difference between measurements of viable cell concentration using methylene blue staining and those using the capacitance reading. Research carried out by a pharmaceutical company has shown the difference in detection between optical density (OD) measurement, respiration quotient (RQ), and capacitance. During a fermentation run, the time to the highest concentration of biomass can vary up to 10 hours. It has also been shown that the concentration of viable biomass dropped dramatically over those 10 hours.