A semicontinuous culture model that links cell growth to extracellular nutrient concentration

Biotechnology and Bioengineering
A V Quinlan

Abstract

During semicontinuous culture, a sample of fixed volume is removed at regular time intervals to make measurements and/or harvest culture components, and an equal volume of fresh medium is immediately added to the culture, thereby instantaneously enhancing nutrient concentrations and diluting cell concentration. The resulting cell concentration versus time curve (i.e., the actual cell growth curve) has a saw-toothed appearance because of the periodic dilution of cell concentration. The observed cell concentrations correspond to the peaks of the saw-toothed curve. Cell growth rates are estimated from the locus of observed cell concentrations (i.e., from the apparent growth curve obtained by connecting the peaks of the saw-toothed curve). The sole preexisting model (Fencl's mode) for estimating cell growth rate is valid only when the cells are growing exponentially at a constant rate between samplings. This model has limited validity: despite the periodic enhancement of nutrient concentration, cell growth between samplings eventually causes nutrient depletion, and the cells cease to grow exponentially. Failure to recognize the limits of validity for Fencl' model has resulted in many erroneous applications of the model and, consequ...Continue Reading

Citations

Mar 5, 1990·Biotechnology and Bioengineering·P J Westgate, A H Emery
Dec 5, 1991·Biotechnology and Bioengineering·S R SchnappP M Hasegawa
Oct 20, 1990·Biotechnology and Bioengineering·G A TruskeyR W Swartz

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