The experiment for which Buchner won the Nobel Prize consisted of producing a cell-free extract of yeast cells and showing that this "press juice" could ferment sugar. This dealt yet another blow to vitalism by showing that the presence of living yeast cells was not needed for fermentation. The cell-free extract was produced by combining dry yeast cells, quartz and kieselguhr and then pulverizing the yeast cells with a pestle and mortar. This mixture would then become moist as the yeast cells' contents would come out of the cells. Once this step was done, the moist mixture would be put through a press and the resulting "press juice" had glucose, fructose, or maltose added and carbon dioxide was seen to evolve, sometimes for days. Microscopic investigation revealed no living yeast cells in the extract. Buchner hypothesized that yeast cells secrete proteins into their environment in order to ferment sugars, but it was later found that fermentation occurs inside the yeast cells. Maria Manasseina claimed to have discovered free-cell fermentation a generation earlier than Buchner.[2]
Though it is believed by some that the Büchner flask and the Büchner funnel are named for him, they are actually named for the industrial chemist Ernst Büchner.[3]
Buchner received the Nobel Prize in Chemistry in 1907.