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Elimination of oscillations in fermentation processes
Author(s) -
Sridhar Lakshmi N.
Publication year - 2011
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.12457
Subject(s) - zymomonas mobilis , hopf bifurcation , fermentation , work (physics) , ethanol fuel , process (computing) , chemistry , residual , biochemical engineering , bifurcation , biological system , mathematics , computer science , thermodynamics , biology , physics , food science , engineering , nonlinear system , quantum mechanics , algorithm , operating system
Fermentation processes that are used to produce ethanol exhibit oscillatory behavior and for periods of time during these oscillations, ethanol production decreases substantially and there is considerable loss of residual substrates. There has been a considerable amount of work demonstrating oscillatory behavior in fermentation processes. The aim of this work is to demonstrate simple strategies to eliminate the oscillatory behavior in fermentation processes involving both Zymomonas mobilis and Saccharomyces cerevisiae . The oscillatory behavior is caused by the existence of Hopf bifurcations and it is demonstrated that very minor changes in the input conditions can eliminate the Hopf bifurcation points. In the case of Zymomonas mobilis , it is shown that the addition of a small amount of substrate and/or the key component of the biomass and/or product in the input stream causes the disappearance of the Hopf bifurcation points while in Saccharomyces cerevisiae fermentation process, a very minor increase in the input oxygen supply produces the same result. The aim of this work is not only to demonstrate the existence of the Hopf bifurcations in the fermentation problems, but also to provide strategies to eliminate them. © 2010 American Institute of Chemical Engineers AIChE J, 2011