S. stipitis and S. cerevisiae were grown on glucose as the sole carbon source under both chemostat and batch conditions. For S. cerevisiae, a Crabtree positive yeast, there is a remarkable metabolic difference during these growth conditions; S. cerevisiae shows respiro-fermentative metabolism in the batch cultures, when glucose is available in excess, while a purely respiratory metabolism in the chemostat cultures when glucose is limiting, is observed. We were interested to see how S. stipitis respond to these differences in glucose concentration, and to establish eventual differences between the two different yeasts.