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.
Departmento de Biotecnologia, Faculdade de Engenharia Química de Lorena, Brazil.
S C
SC
Oliveira
T C
TC
Paiva
A E
AE
Visconti
R
R
Giudici
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