2.3. Analytical methods
Ethanol and residual sugar concentrations in the culture filtrates were determined
by high-performance liquid chromatography (Shimadzu Co. Ltd., Kyoto,
Japan) with a refractive index detector and a Shodex KS-801 column (8.0×300mm;
Showa Denko Co. Ltd., Tokyo, Japan) operating at 80 ◦C with a distilled water mobile
phase at a flow rate of 0.6 ml/min. The theoretical yield of ethanol was defined as
0.51 g of ethanol per gram of glucose (2 mol of ethanol/1 mol of glucose) or xylose
(1.67 mol of ethanol/1 mol of xylose).