For cofermentation studies, 2 ml of a seed culture of strain 1400 or 1400(pLNH32)
was inoculated into 100 ml of YEPD nonselective medium in a 300-ml Erlenmeyer
flask equipped with a side arm. The culture was incubated aerobically at
30°C in a floor shaker at 200 rpm until the density was 400 to 450 KU, and there
was no more than a 20-KU difference between the cultures used in the comparison
studies. Twenty milliliters of 50% glucose and 10 ml of 50% xylose were then
added to each culture, making the final glucose and xylose concentrations approximately
8 and 4%, respectively