Discrimination between ethanol inhibition models in a continuous alcoholic fermentation process using flocculating yeast.
Discrimination between different rival models for describing the inhibitory effect of ethanol both on yeast growth and on fermentation was studied for a continuous process of alcoholic fermentation in a tower reactor with recycling of flocculating cells. Models tested include linear, parabolic, hyperbolic, exponential, and generalized nonlinear power-law types. The best expressions were identified under the criteria that all the kinetic parameters should assume acceptable values in a feasible range and should result in the best fit of the experimental data. The kinetic parameters were estimated from steady-state data of several sugar concentrations in feeding stream (S0 = 160, 170, 180, 190, 200 g/L), constant dilution rate (D = 0.2 h-1), recycle ratio (alpha = 13.6), and temperature (T = 30 degrees C). The best model for the yeast growth was of power-law type, whereas for the product formation the best model was of linear type. These models were able to reproduce the trends of the process variables satisfactorily.
Oliveira
S C
SC
Departmento de Biotecnologia, Faculdade de Engenharia Química de Lorena, Brazil.
Paiva
T C
TC
Visconti
A E
AE
Giudici
R
R
D000431:Ethanol / Q000494:pharmacology*; D005285:Fermentation / Q000187:drug effects*; D007700:Kinetics; D016014:Linear Models; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism
D000431:Ethanol