Fed-batch propionic acid production by Propionibacterium acidipropionici

The batch fermentations were conducted using lactose as the substrate at pH 6.5 and temperature 30 degrees C. Average batch kinetic data was eventuall y used to develop ail unstructured mathematical model. The kinetic paramete rs of the model were determined by non-linear regression technique using th e batch experimental results. Parametric sensitivity analysis showed the ma ximum specific substrate consumption rate (r(s)(max)) and the maintenance e nergy constant (m(s)) to be the most sensitive parameters. The experimental observations in batch fermentation were close to the model predictions. Th e batch model was extrapolated to identify nutrient feeding strategies, whi ch were tested successfully for two different fed-batch fermentations. It d emonstrated enhanced propionic acid productivity. The developed model was f ound suitable for the design of feeding strategies to increase propionic ac id production in fed-batch mode of reactor operation. (C) 2000 Elsevier Sci ence S.A. All rights reserved.