Towards pCO2-optimised Fermentations – Reliable Sampling, pCO2 Control & Cellular Metabolism

Abstract

Current industrial approaches using simple intermittent stripping of dissolved carbon dioxide (pCO(2)) by air or nitrogen when exceeding certain levels may underestimate the influence of intracellular pH (pH(i)) fluctuations in the cells' cytoplasms. In addition, commonly applied sampling procedures do not compensate for pressure and pCO(2) losses, respectively, resulting in erroneous reactor pH(i). To reliably investigate the influence of pCO(2), on industrial high cell density fermentations we developed a simple, yet effective and easily scalable pressure-controlled sampling device for representative display and maintenance of reactor conditions, e.g. whilst dye uptake of the cells for pH(i) measurement by FACS after sampling from pressurized fermenters