Michaelis-Menten-Aiba Kinetics of Batch Ethanol Fermentation using Saccharomyces cerevisiae HBY3 Strain
Author : Azucena, Eric John Flores
Major Adviser : Edwin S. Tapang
Committee Members : Acda, Reynaldo I.; Manoto, Russel D.
Year : 1994
Month : April
Type : Thesis
Degree: BS
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Abstract
The effect of different sugar concentrations on the kinetic parameters of the Michaelis-Menten and Aiba Model Equations using Saccharomyces cerevisiae HBY3 in a batch fermentation was determined.
Five batch fermentations at different initial sugar concentrations were studied, namely 5 g/L, 10 g/L, 40 g/L, 100 g/L and 150 g/L. The operating conditions were at room temperature, with an agitation speed of 250 rpm and an aeration of 1 vvm.
The maximum specific growth rate, µm, maximum production rate, vm, ethanol inhibition constant for growth and production rate, K1 and K2, and the yield factor for product on substrate, Yp/s, of the fermentation models proposed by Aiba (1968) were determined. Results showed that µm and vm increased as the initial sugar was increased. The ethanol inhibition constants, K1 and K2, as well as the yield factor Yp/s, decreased at increased initial sugar due to inhibition.
The values calculated were; for µm (h-1) : 0.37 0.28, 0.31, 0.36 and 1.06; for vm (h-1): 1.10, 0.79, 1.32, 1.09 and 2.05; for K1 (g/L): 0.10, 0.053, 0.071, 0.06 and 0.054; for K2 (g/L): 0.06, 0.059, 0.045, 0.03 and 0.039; for Yp/s (g EtOH/g Sugar) : 0.50, 0.48, 0.46, 0.41 and 0.37; for batch fermentations at 5 g/L, 10 g/L, 40 g/L, 100 g/L and 150 g/L initial sugar concentrations, respectively.
It was also found out that there was shift from near linear to an exponential form of ethanol inhibition in both biomass and product formation rates. A computer software ETHANOL v1.0 was developed and used for the graphical differentiation of the rates of growth, product formation and substrate consumption for the determination of the kinetic parameters.
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