Accurate mass balance and conversion data from integrated operation is needed to fully elucidate the
economics of biofuel production processes. This study explored integrated conversion of corn stover to
ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS)
produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented
to ethanol by the glucose–xylose fermenting bacteria, Zymomonas mobilis 8b. The calculations presented
here account for high solids operation and oligomeric sugars produced during pretreatment, enzymatic
hydrolysis, and fermentation, which, if not accounted for, leads to overestimating ethanol yields. The
calculations are illustrated for enzymatic hydrolysis and fermentation of PCS at 17.5% and 20.0% total
solids achieving 80.1% and 77.9% conversion of cellulose and xylan to ethanol and ethanol titers of
63 g/L and 69 g/L, respectively. These procedures will be employed in the future and the resulting
information used for techno-economic analysis.