In 1680, Antonie van Leeuwenhoek became the first to observe single-celled microorganisms in pond water under a microscope. By 1837, Theodor Schwann, French engineer Charles Cagniard de la Tour, and German pharmacist Friedrich Traugott Kützing independently discovered that yeast is a living organism that reproduces by budding. In 1881, German physician and bacteriologist Robert Koch isolated microorganisms that cause infectious diseases. Then, in 1897, Eduard Buchner demonstrated that it is the action of enzymes in yeast that causes fermentation to occur, not the yeast cell itself.
Louis Pasteur initially made his name as a chemist. When he was appointed Dean of Science at the University of Lille, France, a local wine producer approached him to investigate the problem of souring during fermentation. By the 1850s, fermentation was widely believed to be a purely chemical process, although some scientists, notably Theodor Schwann, disagreed. Schwann observed that yeast is essential for the fermentation process that converts sugar into alcohol and showed that yeast is a living organism, reproducing through budding. Fermentation stops when yeast ceases to reproduce, indicating that it is part of a biological process dependent on the action of a living organism.
0 Comments