The French chemist Louis Pasteur founded zymology, when in 1856 he connected yeast to fermentation.When studying the fermentation of sugar to alcohol by yeast, Pasteur concluded that the fermentation was catalyzed by a vital force, called "ferments", within the yeast cells. The "ferments" were thought to function only within living organisms. "Alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells",he wrote.
Nevertheless, it was known that yeast extracts can ferment sugar even in the absence of living yeast cells. While studying this process in 1897, the German chemist and zymologist Eduard Buchner of Humboldt University of Berlin, Germany, found that sugar was fermented even when there were no living yeast cells in the mixture,by an enzyme complex secreted by yeast that he termed zymase.In 1907 he received the Nobel Prize in Chemistry for his research and discovery of "cell-free fermentation".
One year earlier, in 1906, ethanol fermentation studies led to the early discovery of NAD+.