Yeast addition time was after 1, 2, 3 and 4 days during PS
saccharification. The maximum released glucose from PS
hydrolysate was up to 28.46 kg m3 after 3 days saccharification
(Fig. 4). Although the amount of released glucose reached
a maximum after 3 days saccharification, the highest level of
ethanol production (11.80 kg m3) was achieved when the
yeast was added at 2 days saccharification. Ethanol concentration
was 10.37, 9.55 and 9.59 kg m3 when yeast was added
after 1, 3 and 4 days of PS saccharification, respectively. The
ethanol concentration reached a maximum at 2 days after
yeast addition.