TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred System: The fermentation system further comprises hydrothermal decomposition apparatus, where biomass feedstock is moved by compaction state in its main portion, hot-water supply unit for supplying pressurized hot water to the hydrothermal decomposition apparatus main portion, addition line for adding any one chosen from fermented residue fraction, distillation residue (15a) fraction and their combinations to the tank, first enzyme saccharification tank, first fermentation apparatus, second enzyme decomposition apparatus, sulfuric acid decomposition apparatus and second fermentation apparatus. Preferred Components: The biomass is any one chosen from solid residue fraction, hydrothermally treated fraction and their combination. The fermented residue fraction, distillation residue fraction or their combination is hydrothermally treated and then added to the fermentation tank. The biomass used for saccharification process is cellulose biomass. The biomass is hydrothermally decomposed using pressurized hot water in the hydrothermal decomposition apparatus and extraction fraction containing lignin and hemicellulose component and solid residue fraction containing cellulose are separated. The hydrothermal decomposition apparatus discharges the solid residue fraction into the first enzyme saccharification tank, where cellulose is enzymatically broken down by first enzyme to hexose. The hydrothermal decomposition apparatus discharges the extraction fraction into the second enzyme decomposition apparatus, where hemicellulose is enzymatically broken down to pentose. The extraction fraction containing hemicellulose is further decomposed using sulfuric acid to obtain solution containing pentose. The sugar solution containing hexose and the sugar solution containing pentose are fermented respectively in the first fermentation apparatus and second fermentation apparatus to obtain any one chosen from alcohol (18), petroleum substitutes and amino acids. EXAMPLE - No suitable example given.