Application of a high cell density capacitance sensor to different microorganisms

Abstract

In microbial cultivations there is a great need for online biomass determination, especially in such cases, where classical methods have limitations. Capacitance-based sensors are developed and widely used in stem cell and other cell cultures [1, 2]. In the present study we have tried to apply such a capacitance-based online biomass determination (Incyte, Hamilton AG) for many microorganisms of different types. Since the signal of this sensor is dependent on the polarizability of the measured cells, the applicability of the sensor should be checked for every species. Thus, we developed a method as a preliminary sensor application test which is faster and simpler than testing this sensor directly in real cultivations. We have tested an Incyte sensor with prokaryotic species (Lactobacillus sp., Clostridium) and eucaryotic strains (Saccharomyces cerevisiae, Cryptococcus albidus, Rhizopus oryzae, Chlorella vulgaris, Nannochloropsis oculata). Furthermore, according to our best knowledge this is the first report of a capacitance sensor application for microalgae. Finally, via conductivity measurements of the same sensor, we could even follow product formation in some cases too.