Acetobacter aceti

Acetobacter aceti
Scientific classification
Domain:
Bacteria
Phylum:
Pseudomonadota
Class:
Alphaproteobacteria
Order:
Rhodospirillales
Family:
Acetobacteraceae
Genus:
Acetobacter
Species:
A. aceti
Binomial name
Acetobacter aceti
(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 ethanol 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, water and soil.[1] This microbe lives wherever sugar fermentation occurs. It typically grows on substrates rich in sugars, like glucose or other carbon sources. It thrives best in temperatures that range from 25 to 30 degrees Celsius with a max temperature of 35 degrees Celsius and in pH that ranges from 5.5 to 6.3.[1] For a long time it has been used in the fermentation industry to produce acetic acid from alcohol. A. aceti is an obligate aerobe, which means that it requires oxygen to grow as oxygen is used as the terminal electron acceptor.[2]

Acetobacter aceti is economically important because it is used in the production of vinegar by converting the ethanol in wine or cider 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, due to having an acidified cytoplasm which makes nearly all proteins in the genome to evolve acid stability. A. aceti has become important in helping to understand the process by which proteins can attain acid stability.

History

The history of Acetobacter aceti is intertwined with the history of vinegar production and microbial fermentation. The production of vinegar, which come from fermented fruits or grains, dates back thousands of years. Ancient civilization have used vinegar for medicinal and cooking purposes. As time went on, people paid more and more attention to the process of fermentation, which converts sugars into alcohol and then into vinegar in the presence of oxygen. In the late 19th century, Martinus Beijerinck (Dutch microbiologist) isolated various bacteria involved in vinegar production, specifically the genus Acetobacter.[3] In the early 20th century, scientist Louis Pasteur's research identified the role of Acetobacter aceti in the conversion of alcohol to acetic acid. Today, A. aceti is recognized as a species within the genus Acetobacter, belonging to the family Acetobacteraceae in the class Alphaproteobacteria.[4] Research on A. aceti has expanded to explore their biotechnological applications beyond vinegar production including biofuel production, bioremediation, food fermentation, and synthesis of biopolymers.[5]

Industrial use

Acetic acid production

A. aceti is used for the mass production of acetic acid, the main component in vinegar. During the fermentation process of vinegar production, it 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. A. aceti is widely used in industrial vinegar production due to its ability to produce high concentrations of acetic acid from ethanol while also having a high resistance to acetic acid.[6]

Diabetes

Probiotics have been identified as a method for diabetes treatment. Furthermore, scientists have identified chromium and zinc rich Acetobacter aceti as something that can enhance the hypoglycemic effects of the probiotic. An experiment was conducted in which they compared this Acetobacter aceti to metformin, which is a common treatment for patients with type 2 diabetes. Following the experiment, they were able to conclude that the bacteria, Acetobacter aceti, increased insulin secretion and helped repair damaged pancreatic tissue. [7]

Cellulose production

Cellulose is a carbohydrate, specifically a polysaccharide, which can be found in the cell walls of plants, algae, fungi, and some bacteria. Through its production of acetic acid and oxidation of ethanol, A. aceti plays a crucial role in synthesis of bacterial cellulose. Bacterial cellulose is unique from plant cellulose due to its highly pure and crystalline structure. This bacterial cellulose is valued for its high purity, strength, and unique properties. It is used for production of biofilms, medical dressings, and food products.[8][9]

Biofilm formation

A. aceti is typically known as corrosive as it produces acetic acid which causes severe corrosion of copper and steel in many industrial settings. However, it has also been discovered that when in a solution with ethanol, a biofilm of A. aceti forms and can be used as a protective layer to prevent corrosion of carbon and steel. This is important because if A. aceti biofilms are used to reduce microbiologically induced corrosion, industrial profits will increase.[10]

Safety

A. aceti has not been reported as a human pathogen. Human skin does not provide the bacteria with the optimal conditions for it to grow, which makes it safe to handle in factories that use the species to produce acetic acid. However, some evidence indicates it can be harmful to plants and other flora, though it exists naturally in the world.[11]

Growth

Oxidation is used to stimulate the growth of the A. 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. Acetobacter aceti struggles to grow with a carbon source of glucose. However, is grows well on an ethanol medium.[2] Ethanol is a very important compound for the growth of A. aceti. The oxidation of ethanol leads to acetate which lowers the expression of TCA cycle genes. However, this changed once ethanol was added because acetate began to become consumed which led to a unregulation of the glyoxylate pathway upon ethanol oxidation. This means that ethanol is important as a carbon source for the upregulation of metabolic pathways.[12]

Metabolism

A. aceti is a unique microorganism because of its ability to survive in high concentrations of acetic acid. Acetate overoxidation is due to imbalanced metabolic pathways and pumps. A unique feature that this microorganism contains is an efflux pump and the ability for its metabolism to adapt to different environments. The pump serves as a transport mechanism for toxic particles to travel through the cell membrane and cytoplasm, while helping the cell maintain homeostasis. Following, its metabolism can adapt to its surrounding environment and when needed can express genes that aid in acetate metabolism.[6]

As A. aceti accumulates acetate in the presence of ethanol because of incomplete oxidation,[13] catalyzed by the membrane-bound protein pyrroloquinoline quinone-dependent alcohol dehydrogenase (PQQ-dependent ADH), acetate is also used as a carbon and energy source by the tricarboxylic acid (TCA) cycle after ethanol is depleted. Furthermore, the oxidation of ethanol into acetate leads into the creation of adenosine triphosphate (ATP) because of oxidative phosphorylation. Notably, when ethanol is incompletely oxidized by A. aceti, it represses the TCA cycle in A. aceti and it is used as an energy source and the TCA cycle functions to synthesize cell materials.[14]

References

  1. 1 2 Raspor, Peter; Goranovič, Dušan (January 2008). "Biotechnological Applications of Acetic Acid Bacteria". Critical Reviews in Biotechnology. 28 (2): 101–124. doi:10.1080/07388550802046749. ISSN 0738-8551. PMID 18568850.
  2. 1 2 Sengun, Ilkin Yucel; Karabiyikli, Seniz (May 2011). "Importance of acetic acid bacteria in food industry". Food Control. 22 (5): 647–656. doi:10.1016/j.foodcont.2010.11.008.
  3. ↑ Gomes, Rodrigo José; Borges, Maria de Fátima; Rosa, Morsyleide de Freitas; Castro-Gómez, Raúl Jorge Hernan (2018). "Acetic Acid Bacteria in the Food Industry: Systematics, Characteristics and Applications" (PDF). Food Technology and Biotechnology. 56 (2): 139–151. doi:10.17113/ftb.56.02.18.5593. PMC 6117990. PMID 30228790.
  4. ↑ "National Center for Biotechnology Information". www.ncbi.nlm.nih.gov. Retrieved 2024-03-19.
  5. ↑ Gillis, M.; Kersters, K.; Gossele, F.; Swings, J.; De Ley, J.; MacKenzie, A. R.; Bousfield, I. J. (1983-01-01). "Rediscovery of Bertrand's Sorbose Bacterium (Acetobacter aceti subsp. xylinum): Proposal to Designate NCIB 11664 in Place of NCIB 4112 (ATCC 23767) as the Type Strain of Acetobacter aceti subsp. xylinum: Request for an Opinion". International Journal of Systematic Bacteriology. 33 (1): 122–124. doi:10.1099/00207713-33-1-122. ISSN 0020-7713.
  6. 1 2 Nakano, Shigeru; Fukaya, Masahiro (June 2008). "Analysis of proteins responsive to acetic acid in Acetobacter: Molecular mechanisms conferring acetic acid resistance in acetic acid bacteria". International Journal of Food Microbiology. 125 (1): 54–59. doi:10.1016/j.ijfoodmicro.2007.05.015. PMID 17920150.
  7. ↑ Huang, Yong-Yi; Qin, Xiang-Kun; Dai, Yuan-Yuan; Huang, Liang; Huang, Gan-Rong; Qin, Yan-Chun; Wei, Xian; Huang, Yan-Qiang (2022-06-15). "Preparation and hypoglycemic effects of chromium- and zinc-rich Acetobacter aceti". World Journal of Diabetes. 13 (6): 442–453. doi:10.4239/wjd.v13.i6.442. ISSN 1948-9358. PMC 9210545. PMID 35800410.
  8. ↑ Okiyama, Atsushi; Shirae, Hideyuki; Kano, Hideo; Yamanaka, Shigeru (November 1992). "Bacterial cellulose I. Two-stage fermentation process for cellulose production by Acetobacter aceti". Food Hydrocolloids. 6 (5): 471–477. doi:10.1016/S0268-005X(09)80032-5.
  9. ↑ Dayal, Manmeet Singh; Goswami, Navendu; Sahai, Anshuman; Jain, Vibhor; Mathur, Garima; Mathur, Ashwani (April 2013). "Effect of media components on cell growth and bacterial cellulose production from Acetobacter aceti MTCC 2623". Carbohydrate Polymers. 94 (1): 12–16. doi:10.1016/j.carbpol.2013.01.018. PMID 23544503.
  10. ↑ France, Danielle Cook (2016-07-19). "Anticorrosive Influence of Acetobacter aceti Biofilms on Carbon Steel". Journal of Materials Engineering and Performance. 25 (9): 3580–3589. doi:10.1007/s11665-016-2231-0. ISSN 1059-9495. PMC 5220434. PMID 28082824.
  11. ↑ "Acetobacter aceti Final Risk Assessment – Biotechnology Program Under Toxic Substances Control Act (TSCA) – US EPA". epa.gov. 27 September 2012. Retrieved 1 June 2013.
  12. ↑ Sakurai, Kenta; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo (March 2012). "Changes in the gene expression profile of Acetobacter aceti during growth on ethanol". Journal of Bioscience and Bioengineering. 113 (3): 343–348. doi:10.1016/j.jbiosc.2011.11.005. PMID 22153844.
  13. ↑ Arai, Hiroyuki; Sakurai, Kenta; Ishii, Masaharu (2016), Matsushita, Kazunobu; Toyama, Hirohide; Tonouchi, Naoto; Okamoto-Kainuma, Akiko (eds.), "Metabolic Features of Acetobacter aceti", Acetic Acid Bacteria: Ecology and Physiology, Tokyo: Springer Japan, pp. 255–271, doi:10.1007/978-4-431-55933-7_12, ISBN 978-4-431-55933-7, retrieved 2024-04-04
  14. ↑ Matsushita, Kazunobu; Inoue, Taketo; Adachi, Osao; Toyama, Hirohide (July 1, 2005). "Acetobacter aceti Possesses a Proton Motive Force-Dependent Efflux System for Acetic Acid". Journal of Bacteriology. 187 (13): 4346–4352. doi:10.1128/JB.187.13.4346-4352.2005. ISSN 0021-9193. PMC 1151782. PMID 15968043.
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