Homolaktisk

Homolaktisk refers to a type of fermentation where the primary end product is lactic acid. This process is carried out by microorganisms, typically bacteria, that lack the enzyme lactate dehydrogenase. In homolaktic fermentation, glucose is converted almost exclusively into lactic acid. This is in contrast to heterolaktic fermentation, which produces a mixture of lactic acid, ethanol, and carbon dioxide, or other byproducts.

The biochemical pathway for homolaktic fermentation is the Embden-Myerhof-Parnas (EMP) pathway, also known as the glycolytic pathway. During glycolysis, glucose is broken down into two molecules of pyruvate. In homolaktic fermentation, pyruvate is then reduced to lactate by the enzyme lactate dehydrogenase, which utilizes NADH as a reducing agent. This regeneration of NAD+ from NADH is crucial for the continuation of glycolysis.

Homolaktic fermentation is significant in various industrial applications, most notably in the dairy industry for the production of yogurt, cheese, and other fermented milk products. Bacteria such as Lactobacillus bulgaricus and Streptococcus thermophilus are commonly used in these processes. Beyond dairy, homolaktic fermentation plays a role in the production of sauerkraut, pickles, and certain types of silage. It is also a key process in the muscle cells of animals during strenuous exercise, leading to the buildup of lactic acid and muscle fatigue. The efficiency of homolaktic fermentation, in terms of ATP yield per glucose molecule, is generally higher than that of heterolaktic fermentation.