Application of Computer Control to Yeast Fermentation

Abstract

The objective of comnuter control is to optimize a fermentation process through minimization of manufacturing cost. This involves maximizing productivity for product formation while minimizing the consumption of raw materials. Using online measurement of oxygen consumption and carbon dioxide production as well as mass flow rates of substrate and air, we have applied on-line computer control to the baker’s yeast fermentation, the production of yeast single-cell protein from methanol and the production of yeast from spent sulfite liquor. Using these examples, the methodology and strategy for monitoring and controlling yeast fermentations is discussed. The baker’s yeast fermentation illustrates the application of computer control to a fed batch fermentation. Results from growth of Hansenula polymorpha on methanol focus on the application of computer control to prevent over-feeding of toxic methanol; this is important in start-un and long-term continuous culture. Using the production of Candida utilis from spent sulfite liquor, computer control is used to maintain high productivity cell recycle for yeast production.