This animation focuses on one molecule of glucose turning into pyruvate then into lactic acid. 2 phosphates attach to the lactic acid production pdf of the glucose molecule, splitting the glucose molecule into 2 pyruvate molecules. Then ADP comes and takes the phosphates, creating 2 ATP molecules.
In homolactic fermentation, one molecule of glucose is ultimately converted to two molecules of lactic acid. Heterolactic fermentation, in contrast, yields carbon dioxide and ethanol in addition to lactic acid, in a process called the phosphoketolase pathway. Several chemists discovered during the 19th century some fundamental concepts of the domain of organic chemistry. Even if this chemical process hasn’t been properly described before Pasteur’s work, people had been using microbial lactic acid fermentation for food production much earlier. Chemical analysis of archeological finds showed that milk fermentation uses predate the historical period, its first applications were probably a part of the Neolithic Revolution. With the increasing consumption of milk products these societies developed a lactase persistence by epigenetic inheritance, which means that the milk-digesting enzyme lactase was present in their body during the whole lifetime, so they could drink unfermented milk as adults too. Milk products and their fermentation have had an important influence on some cultures’ development.
This is the case in Mongolia, where people often practice a pastoral form of agriculture. The milk that they produce and consume in these cultures is mainly mare milk and has a long tradition. Overall, the homofermentative lactic acid fermentation converts a six-carbon sugar molecule to two lactic acid molecules, storing the released energy into two ATP molecules. Heterofermentative bacteria produce one mole of lactate from one mole of glucose as well as CO2 and acetic acid or ethanol. Lactic acid fermentation is used in many areas of the world to produce foods that cannot be produced through other methods. The prepared product is rich in lactic acid, and only the beneficial bacteria that can tolerate lactic acid pH survive. It not only assures good quality of nutrients, but it is also a good source of probiotics.
Kimchi also uses lactic acid fermentation. Lactic acid fermentation is also used in the production of sauerkraut. The main type of bacteria used in the production of sauerkraut is of the genus Leuconostoc. As in yogurt, when the acidity rises due to lactic acid-fermenting organisms, many other pathogenic microorganisms are killed.
The bacteria produce lactic acid, as well as simple alcohols and other hydrocarbons. These may then combine to form esters, contributing to the unique flavor of sauerkraut. Lactic acid is a component in the production of sour beers, including Lambics and Berliner Weisses. The main method of producing yogurt is through the lactic acid fermentation of milk with harmless bacteria. For a probiotic yogurt, additional types of bacteria such as Lactobacillus acidophilus are also added to the culture. Lactobacillus fermentation and accompanying production of acid provides a protective vaginal microbiome that protects against the proliferation of pathogenic organisms. Fermented Fruits and Vegetables – A Global SO Perspective”.
Rencontre de Pasteur et de Whitehead dans un bain d’acide lactique. A History of Lactic Acid Making: A Chapter in the History of Biotechnology, chapter 1 and 2. A Brief History of Fermentation, East and West. In History of Soybeans and Soyfoods, 1100 B. Nutrition, population growth and disease: a short history of lactose.
Environmental Microbiology Volume 15, pages 2154-2161. Les dessus et les dessous du lait. Sociologie et politique du lait et de ses dérivés en Mongolie. Archived from the original on 2009-08-02. Lactic acid fermentation in the production of foods from vegetables, cereals and legumes”.