Cell-Free Fermentation

Cell-free fermentation is the discovery that a sugar solution can be fermented into alcohol and carbon dioxide by an extract pressed from broken yeast cells, with no living cell present in the mixture. Eduard Buchner made the discovery in 1897, grinding yeast with sand and kieselguhr and filtering out a cell-free "press juice" that fermented sugar on its own; he named the responsible substance zymase. The result overturned Louis Pasteur's contention that fermentation depended on a living cell's vital force, and gave the first direct demonstration that a process credited to life itself was in fact carried out by molecules, later understood as enzymes, that could be extracted, isolated and studied like any other chemical substance. Buchner's paper, Alkoholische Garung ohne Hefezellen, appeared in the Berichte der Deutschen Chemischen Gesellschaft in 1897 and won him the 1907 Nobel Prize in Chemistry.