It doesn't.
This is anaerobic respiration i.e. respiration in the absence of oxygen
Aerobic because it doesn't require Oxygen to make unlike anaerobic respiration. Thus making it far more efficient even though it causes cramps.
When yeast undergoes anaerobic respiration, it gives off Carbon dioxide (CO2) and Ethanol. The Ethanol is used in alcohol production, bread making, gasohol etc.
Anaerobic respiration only glycolysis occurs which forms 2ATP. However, in aerobic respiration there is the Krebs cycle which is responsible for making 2 ATP and the electron transport chain which is responsible for making 30 ATP. Most textbooks say that for aerobic respiration around 36-38 ATP is made. When compared to the 2 from anaerobic it is a major difference in energy production.
This is caused by a buildup of lactic acid.
When yeasts are used to make bread and for brewing, their ability to respire anaerobically makes them useful. They produce the alcohol for the beer/wine, and the CO2 for the baking. The CO2 makes the bread or pastry rise; the alcohol evaporates during the baking process
The main advantage of aerobic respiration over anaerobic respiration is the production of a significantly larger amount of ATP (energy) per glucose molecule. This allows cells to generate more energy for cellular processes, making aerobic respiration more efficient in providing energy for organisms.
Anaerobic respiration in vinegar making refers to the conversion of sugars in the fruit juice into acetic acid by certain bacteria, such as Acetobacter. During this process, the bacteria do not require oxygen and instead use a different electron acceptor to carry out respiration. This allows the bacteria to convert the sugars into vinegar in the absence of oxygen.
Yeast produces CO2 gas and sometimes ethenol when it metabolizes sugar.
A fermentation process is used to make yogurt. Milk contains the sugar lactose; and some bacteria will ferment lactose to produce lactic acid. the lactic acid clots the milk protein, and give the yogurt its sour taste. Fermentation is just another name for anaerobic respiration.
Alcohol Industry - alcohol fermentation (vodka, whisky) Dairy Industry - milk fermentation (yogurt, buttermilk)