Effect of feeding strategy on Zymomonas mobilis CP4 fed-batch fermentations and mathematical modeling of the system.
In this work, the effect of the feeding strategy in Zymomonas mobilis CP4 fed-batch fermentations on the final biomass and ethanol concentrations was studied. Highest glucose yields to biomass (0.018 g/g) and to ethanol (0.188 g/g) were obtained in fed-batch fermentations carried out using different feeding rates with a glucose concentration in the feed equal to 100 g/l. Lower values (0.0102 g biomass/g glucose and 0.085 g ethanol/ g glucose) were obtained when glucose accumulated to levels higher than 60 g/l. On the other hand, the highest biomass (5 g/l) and ethanol (39 g/l) concentrations were obtained using a glucose concentration in the feed equal to 220 g/l and exponentially varied feeding rates. Experimental data were used to validate the mathematical model of the system. The prediction errors of the model are 0.39, 14.36 and 3.24 g/l for the biomass, glucose and ethanol concentrations, respectively. Due to the complex relationship for describing the specific growth rate, a fed-batch culture in which glucose concentration is constant would not optimize the process.
Bravo
S
S
Department of Chemical Engineering, Universidad de La Frontera, Temuco, Chile.
Mahn
A
A
Shene
C
C
D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D008433:Mathematics; D008954:Models, Biological; D017355:Zymomonas / Q000378:metabolism*
D000431:Ethanol; D005947:Glucose