Specific consumption rates and ethanol metabolic yields for both glucose and xylose were estimated for batch glucose/xylose fermentations. The adapted strain did not show significant changes in both parameters compared to the original strain. Differences between the strains were primarily that the xylose fermentation stalled in the original strain while the fermentation continued in the adapted strain.
Global gene expression and metabolomic analysis were used to determine the differences between the original and the adapted strain during glucose/xylose co-fermentation in the presence of acetic acid. We identified 653 genes that change at least five fold in gene expression between the two strains over the entire course of the fermentation. Of those, 182 genes had >5 fold changes in expression during the xylose-fermenting stage after glucose was fully consumed. Clustering analysis was used to find patterns in these differentially expressed genes over the entire fermentation. Intracellular concentration or 6 metabolites (of 27 metabolites measured) from glycolysis and PPP pathways significantly vary between original and adapted strain.