Author(s)

Ghanem-Lakhal Abdelghani

Département de Génie des Procédés, ENPC, Constantine, Algérie.

In this paper, a study of the bifurcation analysis of fermentation of sugar to ethanol in presence of Saccharomyces cerivisiae at very high gravity is described. The bifurcation analysis was done for a concentration 280 gl⁻¹ of sugar, and the dilution rate was taken as the parameter of bifurcation. Two Hopf bifurcations (HB) at 280 gl⁻¹ were found. At dilution rate of 0.027 h⁻¹ the system exhibits damped oscillations and not sustained oscillations as previously reported because the system is close to a point of attraction, and we can attenuate these oscillations by the choice of initial conditions. The system exhibits sustained oscillations between the two Hopf Bifurcations, the first at 0.08028 h⁻¹ and the second at 0.04395 h⁻¹. These oscillations are the consequence of synchrony between the daughter and the mother yeast. Indeed, it is better to take a dilution rate between the two Hopf bifurcations (self sustained oscillations), in order to increase the ethanol productivity.

Bifurcation, Ethanol, Fermentation, Saccharomyces cerevisiae, Very High Gravity

Abdelghani, G. (2018) Continuous Ethanol Fermentation at Very High Gravity in the Presence of Saccharomyces cerevisiae: A Bifurcation Analysis. Journal of Sustainable Bioenergy Systems, 8, 116-126. doi: 10.4236/jsbs.2018.84009.