O anaerobicism, also called anaerobic breathing, it is a process used by some organisms, such as bacteria, which do not need oxygen for the cellular respiration process. These organisms do not have enzymes responsible for the chemical reactions of the Krebs cycle and the chain respiratory, and for them oxygen is toxic, and for this reason they only grow and reproduce in environments without that gas.
Fermentation, a process contrary to the process of respiration, is carried out by anaerobic organisms, and glucose is broken down without the consumption of oxygen from the environment. As an example, we can mention the bacteria that cause botulism and tetanus, which grow and reproduce in environments where there is little oxygen supply. There are also some organisms that are called facultative anaerobes, as they only breathe anaerobic when they lack oxygen, such as brewer's yeast and muscle cells.
There are several types of fermentation, the most important being lactic and alcoholic fermentation. Lactic fermentation is carried out by anaerobic bacteria called lactobacilli. Lactobacilli are widely used in the production of yogurt and curds, and they can also be found in our intestines, helping to produce several vitamins. Muscle cells can do both aerobic respiration (presence of oxygen) and lactic fermentation. These cells do this process when there is intense and vigorous exercise with a consequent lack of oxygen.
Alcoholic fermentation is carried out by the fungus Saccharomyces cerevisiae. When there is a shortage of oxygen, this fungus carries out alcoholic fermentation, a process used in alcoholic beverages and whose product is carbon dioxide and ethyl alcohol. As it is a facultative anaerobic organism, this fungus, when exposed to environments where there is a large supply of oxygen, will produce water and carbon dioxide, being widely used in cooking.
By Paula Louredo
Graduated in Biology