Hi
There are two types of fermentation:
- Lactic acid fermentation
- Alcoholic fermentation
Both of them are basically methods of anaerobic respiration in
Lactic acid fermentation occurs in some bacteria and in some tissues of animals( like skeletal muscles and Red blood cells). In this process glucose is converted into energy and a by product called Lactate is formed. This type of fermentation is also used in food and brewing industry where lactic acid bacteria are used for the synthesis of different products.
Alcohol fermentation on the other hand is used by some microorganisms like yeast for the production of energy. The byproduct that is formed along with ethanol.
Hope it helps!