Effect of the Feed Substrate Concentration on the Dynamic Performance of the Bioethanol Fermentation Process Using Zymomonas mobiliz

Abstract

In this work, a structured verified nonlinear mathematical model for a single continuous fermenter of bioethanol production using Zymomonas mobiliz is developed to investigate the effect of the feed substrate concentration, which is taken as the main bifurcation parameter for performing a bifurcation analysis. The chaotic, oscillatory, and steady-state behaviors of the fermentation system are investigated. It is found that the system is dominated by oscillatory behavior in the medium gravity (MG) region (80.76 < C so < 213.6), while it is dominated by stable steady state outside this range; however, at high C so and low dilution rate, the chaotic behavior dominates the system. It is found that the fermentation system accomplishes the maximum averages of substrate conversion and bioethanol yield in the range of 80.76 < C so < 97 g/L. These results are in agreement with the experimental results in the literature.

Two‐Parameter Continuation and Bifurcation Strategies for Oscillatory Behavior Elimination from a Zymomonas mobilis Fermentation System

“…All fermentation cultures are assumed to operate isothermally at 30 °C via cooling the CSTR, in order to be able to work at maximum conversion of the substrate. As shown by Mustafa et al 22, 29 the rate of substrate consumption based on the maintenance model can be written as: …”

“…Using two‐parameter techniques, the oscillatory phenomena can then be monitored while changing the values of two parameters. Bifurcation and two‐parameter continuation diagrams are obtained via XPP‐AUTO 2000 20–22. All of the point, periodic, and chaotic attractors can be determined by identifying HB and period doubling points.…”