Gluconacetobacter kombuchae
Scientific Classification [1]
Domain: Bacteria
Phylum: Proteobacteria
Class: Alphaproteobacteria
Order: Rhodospirillales
Family: Acetobacteraceae
Genus: Gluconacetobacter
Species: G. kombuchae
Introduction
G. kombuchae cells are gram-negative, obligate aerobic bacteria that were originally discovered in Kombucha tea cultures in 2007 [2]. Gluconacetobacter are a genus of acetic acid bacteria, in that they oxidize ethanol to acetic acid. This function is key in the production of Kombucha tea, oxidizing the yeast-produced ethanol to acetic acid and other acids and giving the drink its distinctive vinegar-like flavor[3]. Other strains in the Gluconacetobacter genus, such as Gluconacetobacter intermedius and Gluconacetobacter sacchari, have been isolated from Kombucha[1]. Within the Acetobacteraceae family, several members are cellulose-producers, while only seven to date fix nitrogen[2]. G. kombuchae is the first instance of a strain in the family that can both produce cellulose and fix nitrogen[2].
Genome
The closest neighbors phylogenetically to G. kombuchae are other cellulose producing strains G. hansenii (99.1%) and G. entanii (98.6%)[2]. The major difference between these strains is G. kombuchae’s ability to fix nitrogen[2]. G. kombuchae was found to possess the nifH gene responsible for encoding dinitrogenase reductase; a key component of nitrogenase enzyme complex[2]. Some research has suggested that G. kombuchae and G. hansenii may not be truly distinct, but instead are heterotypic synonyms[4].
Morphology
G. kombuchae cells are straight rods, approximately 2.0–3.0 mm length and 0.1–0.2 mm wide, and are found both singly or in bunches[2]. They are motile cells, utilizing polar flagellation[2]. Their colonies, when grown on LGI plates, are smooth, round, dull, dry, white and opaque, 0.5–1.0 mm in diameter after being incubated for 5 days[2].
Growth in Culture
G. kombuchae growth is supported by L-Alanine solely as the source of carbon and nitrogen in LGI[2]. It can also be supported by L-cysteine and L-threonine as carbon and nitrogen sources[2]. It can utilize D-arabinose, D-mannitol, D-sorbitol, and glycerol in the absence of yeast extract, and grows in both 30% glucose and sucrose[2]. To differentiate G. kombuchae from G. hansenii in growth, one can utilize sorbitol as the only carbon source, or else not utilize ethanol, mannitol, and sucrose as carbon sources[2]. To differentiate it from G. entanii, utilizing sorbitol as the only carbon source is effective, as is growing without acetic acid and with D-mannitol[2]. It grows ideally between 2.5 and 6.0 pH[1].
Applications
G. kombuchae, along with other members of the Gluconacetobacter genus such as G. hansenii and G. sacchari, have been proposed to be potential factories in the production of bacterial cellulose[5][6]. G. hansenii, the closest related strain to G. kombuchae (and proposed potential synonym) has been grown in media partly consisting of corn steep liquor as a nitrogen source to reduce production costs in growing bacterial cellulose[5].
References
- ↑ 1.0 1.1 1.2 Sievers, M.; Swings, J. Gluconacetobacter. In Bergey’s Manual of Systematics of Archaea and Bacteria; American Cancer Society, 2015; pp 1–11. https://doi.org/10.1002/9781118960608.gbm00883
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Dutta, D.; Gachhui, R. Nitrogen-Fixing and Cellulose-Producing Gluconacetobacter Kombuchae Sp. Nov., Isolated from Kombucha Tea. Int. J. Syst. Evol. Microbiol. 2007, 57 (Pt 2), 353–357. https://doi.org/10.1099/ijs.0.64638-0.
- ↑ Gomes, R. J.; Borges, M. de F.; Rosa, M. de F.; Castro-Gómez, R. J. H.; Spinosa, W. A. Acetic Acid Bacteria in the Food Industry: Systematics, Characteristics and Applications. Food Technol Biotechnol 2018, 56 (2), 139–151. https://doi.org/10.17113/ftb.56.02.18.5593.
- ↑ Cleenwerck, I.; De Wachter, M.; González, A.; De Vuyst, L.; De Vos, P. Differentiation of Species of the Family Acetobacteraceae by AFLP DNA Fingerprinting: Gluconacetobacter Kombuchae Is a Later Heterotypic Synonym of Gluconacetobacter Hansenii. Int. J. Syst. Evol. Microbiol. 2009, 59 (Pt 7), 1771–1786. https://doi.org/10.1099/ijs.0.005157-0.
- ↑ 5.0 5.1 Costa, A. F. S.; Almeida, F. C. G.; Vinhas, G. M.; Sarubbo, L. A. Production of Bacterial Cellulose by Gluconacetobacter Hansenii Using Corn Steep Liquor As Nutrient Sources. Front Microbiol 2017, 8. https://doi.org/10.3389/fmicb.2017.02027.
- ↑ Trovatti, E.; Serafim, L. S.; Freire, C. S. R.; Silvestre, A. J. D.; Neto, C. P. Gluconacetobacter Sacchari: An Efficient Bacterial Cellulose Cell-Factory. Carbohydrate Polymers 2011, 86 (3), 1417–1420. https://doi.org/10.1016/j.carbpol.2011.06.046.