Analysis of fermentation parameters
Yeast growth was determined by measuring the OD at
600 nm with a spectrophotometer (UV-1700; Shimadzu,
Kyoto, Japan) after washing the yeast cells twice
and resuspending with reverse osmosis water. The
ethanol concentration was analyzed using gas chromatography
(GC-2010 Plus; Shimadzu) equipped with
a flame ionization detector using a capillary column
(0.25 mm ID, 30 m) coated with 0.15 lm (50 %-
cyanopropylphenyl)-dimethylpolysiloxane (DB225;
Agilent, USA).
The ethanol productivity, defined as grams of
ethanol per liter per hour, was calculated from the
final ethanol concentration. The ethanol yield was
calculated based on the initial sugar concentration and
reported as the percentage of the theoretical yield. The
glucose concentration was quantified by HPLC
(LCMS-2010A System; Shimadzu) with an RI detector
and a sugar column (ULTRON PS-80; Shinwa
Chemical Industries).