THE EFFECT OF PH ON KINETIC AND YIELD PARAMETERS DURING THE ETHANOLICFERMENTATION OF D-XYLOSE WITH PACHYSOLEN-TANNOPHILUS

We have studied the ethanolic fermentation of D-xylose with Pachysolen tannophilus in batch cultures. We propose a model to predict variatio ns in D-xylose consumed, and biomass and ethanol produced, in which we include parameters for the specific growth rate, for the consumption of D-xylose and production of ethanol either related or not to growth. The ideal initial pH for ethanol production turned out to be 4.5.. At this pH value the net specific growth rate was 0.26 h-1, biomass yiel d was 0.16 g.g-1, the cell-maintenance coefficient was 0.073 g.g-1.h-1 , the parameter for ethanol production non-related to growth was 0.064 g.g-1.h-1 and the maximum ethanol yield was 0.32 g.g-1.