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PRODUCTION OF YEAST
A general kinetic and mass transfer model to simulate the growth of baker’s yeast in bio-reactors [1-3]
As you can see in the figures which illustrate the experimental and calculated bio-mass, glucose and ethanol concentrations, along with the respiratory quotients, a good fit has been obtained. In particular we can see that the model performs well in the simulation of lag-phases and diauxic growth. Indeed, you can see that in the growth period immediately after an initial lag-phase, the yeast had a high growth rate via a prevalently fermentative metabolic pathway with ethanol production. This is confirmed by the high value of the respiratory quotient. After all the available glucose is consumed, the yeast starts to metabolise ethanol after a new lag-phase. All these aspects of yeast growth are well simulated by the cybernetic model.
[1]Industrial & Engineering Chemistry Research (2003), 42(21), 5109-5116.
[2] Catalysis Today (2001), 66(2-4), 437-445
[3] Chemical Engineering Journal (2001), 82(1-3), 347-354.