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Feed zone micromixing and its effect on continuous cultures of Saccharomyces cerevisiae


Inadequate mixing is known to be a common problem in the scale-up of bioprocesses, often leading to decreases in yield and productivity. To investigate the role of nutrient dispersion in continuous cultures, growth medium was fed into a laminar flow section of a loop that recirculates broth from a laboratory scale bioreactor. The intensity of micromixing at the feed site could be controlled by varying the axial distance a static mixer was placed upstream of the site. The intensity of the turbulent wake shed by the mixer was quantified by laser Doppler velocimetry and the Bourne dye reaction. By decreasing the size of the smallest turbulent eddy in the feed zone, less of the population is exposed to regions of either inadequate or excessive substrate concentrations. Yield vs. dilution rate curves were obtained through various mixing and feeding strategies. Reduced mixing was shown to delay the onset of the Crabtree effect and therefore improve the bioreactor's productivity.


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Print version deaccessioned 2023.

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Saccharomyces cerevisiae


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