**2.4. Analysis**

Saccharides were analyzed on a high-performance liquid chromatography system (LC-20AD, Shimadzu, Kyoto, Japan) equipped with RI detector (RID-10A) using anion ex‐ change column (NH2P-50 4E; Shodex Asahipak, 250 mm in length and 4.6 mm in ID, Yoko‐ hama, Japan). Acetonitrile-water (8:2 v/v) was flowed at 1.0 mL min-1 as mobile phase. As a method to supplement LC analysis of saccarides, the amount of the reducing sugars re‐ leased by the saccharification process was analyzed by a modified Somogyi–Nelson method (Kim and Sakano, 1996) assuming the composition of sugars to be C6H12O6. The amounts of pentose were analyzed by a modified orcinol method using 5-methylresorcinol (orcinol), FeCl3 5H2O, and conc HCl (Fernell and King, 1953). Ethanol was analyzed by gas-liquid chromatography using a Shimadzu gas chromatograph (model GC–2014) and a glass col‐ umn of 5% Thermon 1000 on Sunpak-A (Shimadzu) with 2-propanol as an internal stand‐ ard. Scanning electron microscope (SEM) images were taken on a Hitachi S–4100 (Tokyo, Japan).
