Final answer:
Louis Pasteur was the first to determine that fermentation could occur with enzymes extracted from used, instead of living yeast cells. He discovered this while studying the causes of spoilage in beer and wine in the late 1850s.
Step-by-step explanation:
Louis Pasteur was the first to determine that fermentation could occur with enzymes extracted from used, instead of living yeast cells. In the late 1850s, while studying the causes of spoilage in beer and wine, Pasteur discovered properties of fermentation by microorganisms. He demonstrated that airborne microbes were responsible for food spoilage and fermentation, laying the foundation for the germ theory of disease.