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(Pasteur 1864) Beijerinck 1898
Acetobacter aceti is a Gram negative bacterium that moves using its peritrichous flagella. Louis Pasteur proved it to be the cause of conversion of alcohol to acetic acid in 1864. It is a benign microorganism which is present everywhere in the environment, existing in alcoholic ecological niches which include flowers, fruits, honey bees, as well as in water and soil. It lives wherever sugar fermentation occurs. It grows best in temperatures that range from 25 to 30 degrees Celsius and in pH that ranges from 5.4 to 6.3. For a long time it has been used in the fermentation industry in order to produce acetic acid from alcohol. Acetobacter aceti is an obligate aerobe which means that it requires oxygen to grow; it only has the ability for respiratory metabolism.
Acetobacter aceti is economically important because it is used in the production of vinegar by converting the ethanol in wine into acetic acid. The acetic acid created by A. aceti is also used in the manufacturing of acetate rayon, plastics production, rubber production, and photographic chemicals. A. aceti is considered an acidophile which means it is able to survive in acidic environments. This is due to having an acidified cytoplasm which makes nearly all proteins in the genome to evolve acid stability. Acetobacter aceti has become important in helping us understand the process by which proteins can attain acid stability.
Acetobacter aceti species is used for the mass production of Acetic Acid, the main component in vinegar. During the fermentation process of vinegar production, the bacteria, Acetobacter aceti is used to act on wines and ciders resulting in vinegar with Acetic acid. It can be converted by a silicone tube reactor, which aids the fermentation process with oxidation.
Acetobacter aceti has not been reported as a human pathogen. Human skin does not provide the bacteria with the optimum conditions for it to grow, which makes it safe to handle in factories that use the bacteria to produce acetic acid. However, there have been some evidence of it being harmful to plants and other flora even though it exists naturally in the world.
The oxidation is used in order to stimulate the growth of the Acetobacter aceti. Samples of the bacteria are placed in a few silicone tubes. These tubes are permeable to oxygen, after which they are left in a region warmer than the typical room temperature and cultured.
Pink disease in pineapples
Because the Acetobacter aceti species occurs naturally and is widespread in the world, so far, there is no evidence showing that it is a threat to humans, however, in recent studies, it has been shown that the bacteria has caused some detrimental effects on pineapples. The pink disease in pineapples causes the fruit to turn a slight pink color only to eventually become brown and then rot. The main agent within this pink disease happens to be the bacteria. Similar experiments have also been tested on other fruits such as apples and pears and results end with rotten fruits. However, the bacterium seems to only be effective if the fruit has already been wounded, or have any locations exposing its flesh. The bacteria is also only effective if the temperature surrounding its invasion is warmer than average. With the discovery of other Acetobacter species, there is still skepticism regarding the Acetobacter aceti being the only cause of the pink discoloration disease in pineapples. Studies are still being conducted on other species on the genus Acetobacter because fifteen of its other species have occurred in the results of the rotting fruits as well.
- "Acetobacter aceti Final Risk Assessment – Biotechnology Program Under Toxic Substances Control Act (TSCA) – US EPA". epa.gov. 27 September 2012. Retrieved 1 June 2013.
- "Vinegar Production - FOOD ENGINEERING". sites.google.com. 20 May 2013. Retrieved 1 June 2013.
- Kiyoshi Toda, Tomoko Asakura (June 1994). "Acetic acid production by Acetobacter aceti in a silicone tube bioreactor". Springer Link. Retrieved 1 June 2013.