Fructilactobacillus sanfranciscensis

Last updated

Fructilactobacillus sanfranciscensis
Scientific classification
Domain:
Phylum:
Class:
Order:
Family:
Genus:
Species:
F. sanfranciscensis
Binomial name
Fructilactobacillus sanfranciscensis
(Weiss and Schillinger 1984) Zheng et al. 2020
Synonyms [1]
  • Lactobacillus brevis subsp. lindneri
  • Lactobacillus sanfranciscensiscorrig. (ex Kline and Sugihara 1971) Weiss and Schillinger 1984
  • Lactobacillus sanfrancisco(ex Kline and Sugihara 1971) Weiss and Schillinger 1984

Fructilactobacillus sanfranciscensis is a heterofermentative species of lactic acid bacteria which, through the production mainly of lactic and acetic acids, helps give sourdough bread its characteristic taste. It is named after San Francisco, where sourdough was found to contain the variety, though it is dominant in Type I sourdoughs globally. [2] [3] In fact, F. sanfranciscensis has been used in sourdough breads for thousands of years, and is used in 3 million tons of sourdough goods yearly. [4] For commercial use, specific strains of F sanfranciscensis are grown on defined media, freeze-dried, and shipped to bakeries worldwide.

Contents

Overview

Fructilactobacillus sanfranciscensis was first known to be isolated in 1971 by Kline and Sugihara. As lactic acid bacteria, the strains are Gram-positive, slender, rod-shaped, nonsporulating, and non-motile. [5] They are also obligately heterofermentative, meaning that they can convert hexose sugars into not just lactic acid, but also ethanol, CO2, and/or acetic acid. [6] This heterofermentative ability is key for this species’ role in creating the unique flavor of sourdough bread.

Sourdough starters are leavened by a mixture of yeast and lactobacilli in a ratio of about 1:100. The yeast is most commonly Kasachstania humilis (formerly Candida humilis or C. milleri). This yeast cannot metabolize the maltose found in the dough, while the Fructilactobacillus requires maltose. [7] They therefore act without conflict for substrate, with lactobacilli utilizing maltose and the yeast utilizing the other sugars, including the glucose produced by the F. sanfranciscensis.

Growth Conditions

External conditions such as acidity and temperature affect the growth rates of F. sanfranciscensis. A temperature of 33 °C (91 °F) leads to maximum growth rates, whereas temperatures over 41 °C (105 °F) completely inhibit the bacteria growth. And in terms of pH, most strains can tolerate levels as low as 3.6, but the optimal range for growth is slightly higher (around 4-5) as it is also the optimum pH for some of the key proteins involved—for example, those involved in maltose transport function optimally at 5.2-5.6. [6] However, there is lots of intraspecies diversity within Fructilactobacillus sanfranciscensis, so the optimal temperature and pH for growth will vary from strain to strain, and depend on a variety of factors—namely, the type of carbon source for metabolism, and the resulting proteins involved. For instance, a common yeast in sourdough, K. humilis, prefers 27 °C (81 °F) and will not grow above 36 °C (97 °F). [8]

Genome

The genomes of Fructilactobacillus sanfranciscensis strains are often quite small—in fact, they are suggested to be the smallest of all the lactobacilli. [9] It is even thought that many genes within F. sanfranciscensis (that are also present in other heterofermentative lactobacilli) were lost or deleted via mutation. However, despite this loss of genes and overall smaller genome size, the F. sanfranciscensis genomes are relatively dense in ribosomal RNA (rRNA) operons, which contributes to more rapid growth and protein production. Additionally, the smaller genome allows for a significant amount of metabolic energy to be conserved. [10] Overall, the genome length can vary from strain to strain; some can have more plasmids than others, some have slightly longer circular chromosomes, etc. But most strains share this characteristically small genome with a high density of rRNA operons, which allow for relatively fast growth rates.

Related Research Articles

<span class="mw-page-title-main">Sourdough</span> Bread

Sourdough or sourdough bread is a bread made by the fermentation of dough using wild lactobacillaceae and yeast. Lactic acid from fermentation imparts a sour taste and improves keeping qualities.

<i>Lactobacillus</i> Genus of bacteria

Lactobacillus is a genus of gram-positive, aerotolerant anaerobes or microaerophilic, rod-shaped, non-spore-forming bacteria. Until 2020, the genus Lactobacillus comprised over 260 phylogenetically, ecologically, and metabolically diverse species; a taxonomic revision of the genus assigned lactobacilli to 25 genera.

<i>Lactobacillus acidophilus</i> Species of bacterium

Lactobacillus acidophilus is a rod-shaped, Gram-positive, homofermentative, anaerobic microbe first isolated from infant feces in the year 1900. The species is most commonly found in humans, specifically the gastrointestinal tract, oral cavity, and vagina, as well as various fermented foods such as fermented milk or yogurt. The species most readily grows at low pH levels, and has an optimum growth temperature of 37 °C. Certain strains of L. acidophilus show strong probiotic effects, and are commercially used in dairy production. The genome of L. acidophilus has been sequenced.

Lactiplantibacillus plantarum is a widespread member of the genus Lactiplantibacillus and commonly found in many fermented food products as well as anaerobic plant matter. L. plantarum was first isolated from saliva. Based on its ability to temporarily persist in plants, the insect intestine and in the intestinal tract of vertebrate animals, it was designated as a nomadic organism. L. plantarum is Gram positive, bacilli shaped bacterium. L. plantarum cells are rods with rounded ends, straight, generally 0.9–1.2 μm wide and 3–8 μm long, occurring singly, in pairs or in short chains. L. plantarum has one of the largest genomes known among the lactic acid bacteria and is a very flexible and versatile species. It is estimated to grow between pH 3.4 and 8.8. Lactiplantibacillus plantarum can grow in the temperature range 12 °C to 40 °C. The viable counts of the "L. plantarum" stored at refrigerated condition (4 °C) remained high, while a considerable reduction in the counts was observed stored at room temperature.

<i>Lacticaseibacillus casei</i> Species of bacterium

Lacticaseibacillus casei is an organism that belongs to the largest genus in the family Lactobacillaceae, a lactic acid bacteria (LAB), that was previously classified as Lactobacillus casei. This bacteria has been identified as facultatively anaerobic or microaerophilic, acid-tolerant, non-spore-forming bacteria.

<span class="mw-page-title-main">Lactic acid bacteria</span> Order of bacteria

Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation, giving them the common name lactic acid bacteria (LAB).

Limosilactobacillus reuteri is a lactic acid bacterium found in a variety of natural environments, including the gastrointestinal tract of humans and other animals. It does not appear to be pathogenic and may have health effects.

<span class="mw-page-title-main">Proofing (baking technique)</span> Process by which a yeast-leavened dough rises

In cooking, proofing is a step in the preparation of yeast bread and other baked goods in which the dough is allowed to rest and rise a final time before baking. During this rest period, yeast ferments the dough and produces gases, thereby leavening the dough.

<span class="mw-page-title-main">Lactobacillaceae</span> Family of bacteria

The Lactobacillaceae are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the Lactobacillaceae, the pathway used for hexose fermentation is a genus-specific trait. Lactobacillaceae include the homofermentative lactobacilli Lactobacillus, Holzapfelia, Amylolactobacillus, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Loigolactobacillus, Lacticaseibacillus, Latilactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus, and Lactiplantibacillus; the heterofermentative lactobacilli Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Levilactobacillus, Secundilactobacillus, and Lentilactobacillus, which were previously classified in the genus Lactobacillus; and the heterofermentative genera Convivina, Fructobacillus, Leuconostoc, Oenococcus, and Weissella which were previously classified in the Leuconostocaceae.

Levilactobacillus brevis is a gram-positive, rod shaped species of lactic acid bacteria which is heterofermentative, creating CO2, lactic acid and acetic acid or ethanol during fermentation. L. brevis is the type species of the genus Levilactobacillus (previously L. brevis group), which comprises 24 species. It can be found in many different environments, such as fermented foods, and as normal microbiota. L. brevis is found in food such as sauerkraut and pickles. It is also one of the most common causes of beer spoilage. Ingestion has been shown to improve human immune function, and it has been patented several times. Normal gut microbiota L. brevis is found in human intestines, vagina, and feces.

<span class="mw-page-title-main">Vaginal flora</span> Microorganisms present in the vagina

Vaginal flora, vaginal microbiota or vaginal microbiome are the microorganisms that colonize the vagina. They were discovered by the German gynecologist Albert Döderlein in 1892 and are part of the overall human flora. The amount and type of bacteria present have significant implications for an individual's overall health. The primary colonizing bacteria of a healthy individual are of the genus Lactobacillus, such as L. crispatus, and the lactic acid they produce is thought to protect against infection by pathogenic species.

Limosilactobacillus fermentum is a Gram-positive species in the heterofermentative genus Limosilactobacillus. It is associated with active dental caries lesions. It is also commonly found in fermenting animal and plant material including sourdough and cocoa fermentation. A few strains are considered probiotic or "friendly" bacteria in animals and at least one strain has been applied to treat urogenital infections in women. Some strains of lactobacilli formerly mistakenly classified as L. fermentum have since been reclassified as Limosilactobacillus reuteri. Commercialized strains of L. fermentum used as probiotics include PCC, ME-3 and CECT5716

<i>Latilactobacillus sakei</i> Species of bacterium

Latilactobacillus sakei is the type species of the genus Latilactobacillus that was previously classified in the genus Lactobacillus. It is homofermentative; hexoses are metabolized via glycolysis to lactic acid as main metabolite; pentoses are fermented via the Phosphoketolase pathway to lactic and acetic acids.

Limosilactobacillus mucosae is a rod shaped species of lactic acid bacteria first isolated from pig intestines. It has mucus-binding activity. The species is an obligate anaerobe, catalase-negative, doesn't form spores and is non-motile. Its type strain is S32T, and has been found to be most closely related to Limosilactobacillus reuteri.

Limosilactobacillus pontis is a rod-shaped, Gram-positive facultatively anaerobic bacterium. Along with other Lactobacillus species, it is capable of converting sugars, such as lactose, into lactic acid. Limosilactobacillus pontis is classified under the phylum Bacillota, class Bacilli, and is a member of the family Lactobacillaceae and is found to be responsible for the fermentation of sourdough, along with many other Lactobacillus species. This microorganism produces lactic acid during the process of fermentation, which gives sourdough bread its characteristic sour taste.

Lactiplantibacillus fabifermentans is a member of the genus Lactiplantibacillus and a type of lactic acid bacteria (LAB), a group of Gram-positive bacteria that produce lactic acid as their major fermented end product and that are often involved in food fermentation. L. fabifermentans was proposed in 2009 as a new species, after the type strain LMG 24284T has been isolated from Ghanaian cocoa fermentation. Analysis of the 16S rRNA gene sequence demonstrated that this species is a member of the Lactobacillus plantarum species group but further analysis demonstrated that it is possible to differentiate it from the nearest neighbors by means of DNA-DNA hybridization experiments, pheS sequence analysis, whole-cell protein electrophoresis, fluorescent amplified fragment length polymorphism analysis and biochemical characterization.

Fructilactobacillus fructivorans is a gram-positive bacteria and a member of the genus Fructilactobacillus in the family Lactobacillaceae. It is found in wine, beer, grape must, dairy, sauerkraut, meat, and fish. They are facultative anaerobics and experience best growth in environments with 5-10% CO2. Temperature for growth is between 2 °C and 53 °C, with the optimum temperature between 30 °C and 40 °C and a pH level between 5.5 and 6.2. The bacterium is rod shaped and can be found in the following forms: single, pairs, chains of varying lengths, or long curved filaments. Lactobacillus fructivorans is non-motile. The main end product of the metabolic process is lactate, although ethanol, acetate, formate, CO2, and succinate may also be produced.

Kazachstania humilis is a species of yeast in the genus Kazachstania. It commonly occurs in sourdough and kefir cultures, along with different species of lactic acid bacteria. K. humilis is the most representative yeast species found in type I sourdough ecosystems. The effects of electric field strength, pulse width and frequency, or pulse shape is significant on the membranes of Candida humilis, but not very noticeable.

Limosilactobacillus is a thermophilic and heterofermentative genus of lactic acid bacteria created in 2020 by splitting from Lactobacillus. The name is derived from the Latin limosus "slimy", referring to the property of most strains in the genus to produce exopolysaccharides from sucrose. The genus currently includes 31 species or subspecies, most of these were isolated from the intestinal tract of humans or animals. Limosilactobacillus reuteri has been used as a model organism to evaluate the host-adaptation of lactobacilli to the human and animal intestine and for the recruitment of intestinal lactobacilli for food fermentations.

References

  1. Zheng, Jinshui; Wittouck, Stijn; Salvetti, Elisa; Franz, Charles M.A.P.; Harris, Hugh M.B.; Mattarelli, Paola; O’Toole, Paul W.; Pot, Bruno; Vandamme, Peter; Walter, Jens; Watanabe, Koichi (2020). "A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae". International Journal of Systematic and Evolutionary Microbiology. 70 (4): 2782–2858. doi: 10.1099/ijsem.0.004107 . hdl: 10067/1738330151162165141 . ISSN   1466-5026. PMID   32293557.
  2. Gänzle, Michael G.; Zheng, Jinshui (2019-08-02). "Lifestyles of sourdough lactobacilli - Do they matter for microbial ecology and bread quality?". International Journal of Food Microbiology. 302: 15–23. doi:10.1016/j.ijfoodmicro.2018.08.019. ISSN   1879-3460. PMID   30172443. S2CID   52143236.
  3. De Vuyst, Luc; Van Kerrebroeck, Simon; Leroy, Frédéric (2017). "Microbial Ecology and Process Technology of Sourdough Fermentation". Advances in Applied Microbiology. 100: 49–160. doi:10.1016/bs.aambs.2017.02.003. ISBN   9780128120484. ISSN   0065-2164. PMID   28732554.
  4. Rudi F. Vogel; Melanie Pavlovic; Matthias A. Ehrmann; Arnim Wiezer; Heiko Liesegang; Stefanie Offschanka; Sonja Voget; Angel Angelov; Georg Bocker; Wolfgang Liebl (1 September 2011). "Genomic analysis reveals Lactobacillus sanfranciscensis as stable element in traditional sourdoughs". Microbial Cell Factories. 10 (Suppl 1): S6. doi: 10.1186/1475-2859-10-S1-S6 . PMC   3231932 . PMID   21995419.
  5. Kline, L.; Sugihara, T. F. (March 1971). "Microorganisms of the San Francisco sour dough bread process. II. Isolation and characterization of undescribed bacterial species responsible for the souring activity". Applied Microbiology. 21 (3): 459–465. doi:10.1128/am.21.3.459-465.1971. ISSN   0003-6919. PMID   5553285.
  6. 1 2 Gobbetti, M.; Corsetti, A. (April 1997). "Lactobacillus sanfrancisco, a key sourdough lactic acid bacterium: a review". Food Microbiology. 14 (2): 175–187 via Elsevier Science Direct.
  7. Neubauer H, Glaasker E, Hammes WP, Poolman B, Konings WN (1994). "Mechanism of maltose uptake and glucose excretion in Lactobacillus sanfrancisco". J Bacteriol. 176 (10): 3007–12. doi:10.1128/jb.176.10.3007-3012.1994. PMC   205458 . PMID   8188601.
  8. Ganzle MG, Ehmann M, Hammes WP (1998). "Modeling of Growth of Lactobacillus sanfranciscensis and Candida milleri in Response to Process Parameters of Sourdough Fermentation". Appl Environ Microbiol. 64 (7): 2616–2623. Bibcode:1998ApEnM..64.2616G. doi:10.1128/AEM.64.7.2616-2623.1998. PMC   106434 . PMID   9647838.
  9. Vogel, R.F.; Pavlovic, M.; Ehrmann, M.A.; Wiezer, A.; Liesegang, H.; Offschanka, S.; Voget, S.; Angelov, A.; Böcker, G.; Liebl, W. (September 2011). "Genomic analysis reveals Lactobacillus sanfranciscensis as stable element in traditional sourdoughs" (PDF). Microbial Cell Factories. 10 (Supplementary 1): S6 via NCBI.
  10. Rogalski, E.; Ehrmann, M.A.; Vogel, R.F. (February 2021). "Intraspecies diversity and genome-phenotype-associations in Fructilactobacillus sanfranciscensis". Microbiological Research. 243 via Elsevier Science Direct.