The alkali-treated rice straw was partially hydrolyzed for
2 h at 50°C, prior to yeast inoculation, to decrease the
viscosity of the suspension and to improve the reproducibility
of the results. For the saccharification of
rice straw, a combination of cellulase (Celluclast 1.5 L),
β-glucosidase (Novozyme 188), and enzyme complex
(Ultraflo L) was used for enzymatic saccharification.
All enzymes were obtained from Novozymes Japan
(Chiba, Japan). The enzyme activity of Celluclast 1.5 L
was 80 FPU/mL; β-glucosidase with an enzyme activity
of 322 CBU/mL was used to hydrolyze cellobiose.