Sporolactobacillus

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Sporolactobacillus
Systematics
Domain : Bacteria (bacteria)
Department : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Sporolactobacillaceae
Genre : Sporolactobacillus
Scientific name
Sporolactobacillus
Kitahara and Suzuki 1963

Sporolactobacillus is a genus of bacteria . The type species is Sporolactobacillus inulinus , first described by Kitahara and Suzuki in 1963, expanded by Kitahara and Lai in 1967. Sporolactobacillus speciesare spore-forming lactic acid bacteria .

features

Appearance

The cells of the species of Sporolactobacillus are gram positive . These are straight rods with a diameter of 0.4 to 1.0 μm and a length of 2.0 to 4.0 μm. They occur singly, in pairs, or less often in chains. The species are mostly motile . The movement takes place with the help of peritrichal flagella . Sporolactobacillus forms endospores as a form of persistence. The endospores are ellipsoidal with a diameter of 0.9-1.4 μm and a length of 1.0-2.1 μm. They are formed terminally or subterminally in the mother cell, which swells in the process.

On solid culture media , the cells grow into gray to white, very small colonies . They are round when viewed from above, convex and shiny when viewed from the side. If the culture medium contains calcium carbonate , this is dissolved by the formation of lactic acid, so that a clear halo can be seen around the colonies.

Growth and metabolism

All types of Sporolactobacillus are heterotrophic , they do not photosynthesize . The representatives of the genus are facultatively anaerobic or microaerophilic , i. H. Growth takes place with the complete exclusion of oxygen or with a low proportion of oxygen. The enzyme catalase is not present. You can use different carbohydrates for energy production in one fermentation .

Like the lactic acid bacteria , Sporolactobacillus produces lactic acid in a fermentation that is consequently referred to as lactic acid fermentation . A distinction is made between homofermentative and heterofermentative types. The representatives of Sporolactobacillus are homofermentative, they almost exclusively produce lactic acid from glucose . In the type strain of Sporolactobacillus inulinus , this is predominantly (> 99%) D - (-) - lactic acid ( syn .: ( R ) -lactic acid), which is also known as levorotatory lactic acid . A mixture of D - (-) - and L - (+) - lactic acid has also been found in other species .

The cultivation of Sporolactobacillus takes place in or on nutrient media that are also suitable for lactic acid bacteria, e.g. B. on MRS agar , a nutrient medium that enables the growth of fastidious lactic acid bacteria because it contains complex growth factors . Which growth factors Sporolactobacillus actually needs has not yet been clarified for most species. The nutrient medium is usually incubated at 30–37 ° C. A gas atmosphere with 5% carbon dioxide is recommended, as it only multiplies very slowly under normal air. Most of the strains examined grow at temperatures between 20 and 40 ° C, with optimal reproduction at around 30 ° C. Because Sporolactobacillus produces lactic acid, it is able to grow even at low pH levels . In the case of S. inulinus a pH value of 3.2–3.8 was measured in the medium, and a pH value of 4.4 for other species.

The spore formation does not take place automatically, but is triggered by certain environmental influences on the cells. A nutrient medium, the components of which promote spore formation, has been described. It contains, among other things, tomato juice , which is often used as a component of nutrient media for lactic acid bacteria, ammonium sulfate and starch . The endospores are heat- resistant , they can withstand heating to 70-80 ° C for 10 minutes and after that can germinate, by heating to 90 ° C for 10 minutes but they are inactivated. As is common with bacterial endospores, they contain dipicolinic acid .

Occurrence and ecology

The bacterium for which the genus is described was isolated from chicken feed. Almost all other species discovered so far were found in the rhizosphere or other soil samples . The sites are predominantly in Japan and Southeast Asia . Two strains have been isolated in the United States , but 700 samples have been tested, suggesting that Sporolactobacillus is not common.

Some species are mesophilic ; H. they prefer medium temperatures for growth. Sporolactobacillus lactosus, for example, shows growth at 45 ° C, with many strains also growing at 15 ° C.

Systematics

The type species Sporolactobacillus inulinus was first described by Kitahara and Suzuki in 1963 . They discovered a bacterium in chicken feed that they believe is an intermediate form of the genera Lactobacillus (because of lactic acid fermentation) and Clostridium (because of the formation of spores). They proposed a new subgenus (subgenus, abbreviated as subgen.) Sporolactobacillus in the family Lactobacillaceae . The type species was designated by them as Sporolactobacillus (subgen. Lactobacillus ) inulinus , with the result that the genus Lactobacillus was downgraded to the rank of a subgenus. It is likely that the correct name should be Lactobacillus (subgen. Sporolactobacillus ) inulinus . Later the kind of Kitahara et al. a. only referred to as Sporolactobacillus inulinus and thus established Sporolactobacillus as a genus.

In 1972 the genus was then placed in the Bacillaceae family . Only in 2010 was Ludwig u. a. established a new family Sporolactobacillaceae , the type genus of which is Sporolactobacillus . The Sporolactobacillaceae family belongs to the order Bacillales , not the order Lactobacillales , which contains many lactic acid bacteria. Both orders belong to the Firmicutes department .

The generic name refers to the occurrence of lactic acid bacteria ( Latin lactis , "milk"), the appearance of the cells (Latin bacillus , "small rod") and the ability to form spores ( Greek spora , "spore"). Sporolactobacillus is therefore a rod-shaped bacterium in milk that can form spores. In fact, Sporolactobacillus does not occur in milk, the component of the generic name only refers to the similarity with the genus Lactobacillus , which does not form spores.

The genus includes the following species (as of July 1, 2018):

swell

literature

  • Paul Vos, George Garrity, Dorothy Jones, Noel R. Krieg, Wolfgang Ludwig, Fred A. Rainey, Karl-Heinz Schleifer, William B. Whitman: Bergey's Manual of Systematic Bacteriology: Volume 3: The Firmicutes . Springer, 2009, ISBN 978-0-387-95041-9 .
  • Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria, Volume 4: Bacteria: Firmicutes, Cyanobacteria . 3. Edition. Springer-Verlag, New York 2006, ISBN 978-0-387-25494-4 .

Individual evidence

  1. ^ A b Paul Vos, George Garrity, Dorothy Jones, Noel R. Krieg, Wolfgang Ludwig, Fred A. Rainey, Karl-Heinz Schleifer, William B. Whitman: Bergey's Manual of Systematic Bacteriology: Volume 3: The Firmicutes . Springer, 2009, ISBN 978-0-387-95041-9 .
  2. ↑ a b c d e f Dieter Claus, Dagmar Fritze, Miloslav Kocur: Genera Related to the Genus Bacillus - Sporolactobacillus, Sporosarcina, Planococcus, Filibacter and Caryophanon (Chapter 1.2.19) . In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria, Volume 4: Bacteria: Firmicutes, Cyanobacteria . 3. Edition. Springer-Verlag, New York 2006, ISBN 978-0-387-25494-4 , pp. 631-635 , doi : 10.1007 / 0-387-30744-3_19 .
  3. ↑ a b Kakuo Kitahara, Jiro Suzuki: Sporolactobacillus nov. subgen. In: The Journal of General and Applied Microbiology. Volume 9, Number 1, 1963, pp. 59-71, ISSN  1349-8037 . doi : 10.2323 / jgam.9.59 .
  4. ^ A b c Jean Euzéby, Aidan C. Parte: Genus Sporolactobacillus. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved July 11, 2018 .
  5. ↑ unknown: List of new names and new combinations previously effectively, but not validly, published - Validation List no.132 . In: International Journal of Systematic and Evolutionary Microbiology . tape 60 , no. 3 , March 8, 2010, ISSN  1466-5026 , p. 469-472 , doi : 10.1099 / ijs.0.022855-0 .