Saccharide-solution producing apparatus, fermentation system, saccharide-solution producing method, and fermentation method

A saccharide-solution producing method comprising:

• obtaining, from a single starting material, a cellulosic biomass material comprising a cellulose component, a lignin component and a hemicellulose component, and a carbohydrate-based material comprising starch as a main component;
• hydrothermally decomposing the cellulosic biomass material to produce a solid residual fraction and a hydrothermally discharged fraction, the solid residual fraction containing the cellulose component and the hydrothermally discharged fraction containing the lignin component and the hemicellulose component;
• saccharifying at least one of the solid residual fraction and the hydrothermally discharged fraction with one or more enzymes to produce a diluted saccharide solution having a concentration of 0.1 mass % to 15 mass %;
• storing the carbohydrate-based material in a storage tank;
• transferring the carbohydrate-based material from the storage tank to an enzymatic saccharification tank;
• in the enzymatic saccharification tank, producing a starch-based saccharide solution from the carbohydrate-based material, the starch-based saccharide solution having a concentration higher than the diluted saccharide solution;
• diluting the concentration of the starch-based saccharide solution with water to form a diluted starch-based saccharide solution;
• supplying the diluted saccharide solution into the enzymatic saccharification tank containing the diluted starch-based saccharide solution, wherein the concentration of the diluted starch-based saccharide solution is decreased with the water and the diluted saccharide solution to produce a final saccharide solution having a predetermined concentration.