Fermentation system and fermentation method using saccharide solution

A fermentation method for two saccharide solutions comprising:

• A. hydrothermally treating a first biomass feedstock containing minerals and mineral salts with hot compressed water to extract minerals and mineral salts into the hot water while leaving the cellulose, lignin, and hemicellulose in a treated feedstock;
• B. hydrothermally treating the treated feedstock from step A at a temperature greater than 140° C. to extract the lignin and hemicellulose into the water, while leaving the cellulose in the solid residue;
• C. transferring the solid residue containing cellulose from step B in an enzymatic saccharification tank in order to be enzymatically saccharified to produce a first saccharide solution;
• D. fermenting the first saccharide solution from step C in a fermentation vessel containing yeast to be fermented into a first fermentation liquor;
• E. producing a second saccharide solution from a second biomass feedstock which is materially different from the first biomass feedstock;
• F. transferring the second saccharide solution from step E to a second fermentation vessel containing yeast to produce a second fermentation liquor and a yeast residue, wherein the extracted minerals and mineral salts from step A are added to the second fermentation vessel to improve the fermentation of said second saccharide solution;
• G. distilling the second fermentation liquor from step F in a distillation column producing alcohol and a distillation residue;
• H. combining the yeast residue of step F and the distillation residue of step G into a vessel and hydrothermally decomposing the combination to produce a hydrothermally treated product including minerals and mineral salts;
• and
• I. directly adding the hydrothermally treated product from step H to the second fermentation vessel in step F.