Thermobacillus xylanilyticus

from Wikipedia, the free encyclopedia
Thermobacillus xylanilyticus
Systematics
Department : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Paenibacillaceae
Genre : Thermobacillus
Type : Thermobacillus xylanilyticus
Scientific name
Thermobacillus xylanilyticus
( Touzel et al. 2000)

Thermobacillus xylanilyticus is a species of Firmicutes bacteria .

features

Appearance

The cells of Thermobacillus xylanilyticus are straight rods with pointed ends with a length of 2.0 to 2.8 μm and a width of 0.4 to 0.5 μm. The cells occur individually, in pairs or occasionally in chains. Thermobacillus xylanilyticus has no flagella and is not motile . The Gram test is negative, although it is clearly a gram-positive cell wall structure. The bacterium forms ellipsoidal endospores within swollen sporangia.

Growth and metabolism

The species Thermobacillus xylanilyticus is aerobic . The bacterium needs CO 2 . It is thermophilic , optimal growth occurs at 55 ° C, the maximum temperature for growth is 63 ° C. Tolerated pH values ​​are between 6.5 and 8.5. Optimal growth occurs at a pH of 7.8.

The bacterium can hydrolytically break down the protein esculin . The test for hydrolysis of starch also turns out positive, whereas gelatine and casein are not hydrolyzed. The catalase test is positive, the oxidase test and the urease test are negative. Nitrate is not reduced.

It can u. a. Use the following molecules as a carbon source for growth: cellobiose , fructose , galactose , lactose , mannose , raffinose , trehalose , glycerol tributyrate and xylose . Not used are e.g. E.g .: ribitol , citrate , galactitol , erythritol , inulin , salicin , sorbitol and succinic acid .

The bacterium produces large amounts of the enzyme xylanase , hence the species name. This enzyme is used to break down xylans , a component of hemicellulose in plants.

Chemotaxonomic Features

The GC content in the DNA is 57.5 mol percent. The predominant menaquinone present is MK-7. The dominant fatty acid is iso -C16: 0 ( iso- hexadecanoic acid).

Systematics

The isolated strain was first assigned to the genus Bacillus . On the basis of further investigations that led to the separation of several species from the genus Bacillus , this strain was assigned to the newly created genus Thermobacilus . Thermobacillus belongs to the family Paenibacillaceae of the order Bacillales . At the moment (March 2019) two species are assigned to the genus Thermobacillus , besides T. xylanilyticus the species T. composti , which Keiko Watanabe et al. has been described. This species is also thermophilic, but tolerates higher pH values ​​than T. xylanilyticus , the optimal value is 9, it tolerates values ​​up to 10.1. Other differences are e.g. B. in the predominant menaquinone (in T. composti MK-6 is the most common menaquinone) and in the dominant fatty acids. Like T. xylanilyticus, it is also able to break down xylan .

Thermobacillus xylanilyticus can be regarded as closely related to Paenibacillus on the basis of analysis of the 16S rRNA . In addition to the precise 16S rRNA analysis, the missing flagellum, the dominant fatty acids and the GC content can also be used to differentiate.

etymology

The generic name is derived from the Greek adjective thermos (hot) and the Latin word bacillus (narrow rod). The species name T. xylanilyticus refers to xylan , a vegetable polysaccharide, lutikos is Greek and means "able to dissolve", the bacterium can break down xylan.

Ecology and use

It is believed that Thermobacillus xylanilyticus occurs mainly in warm habitats with a lot of decayed plant material. It is able to break down xylan, which is a heteropolysaccharide which is contained in the hemicelluloses within the cell walls of plants. The bacterium is therefore of interest for the industrial production of vegetable fuels or the manufacture of chemicals such as ethanol from vegetable biomass.

Individual evidence

  1. ↑ a b c d e f 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 Keiko Watanabe, Norio Nagao, Shuich Yamamoto, Tatsuki Toda and Norio Kurosawa: Thermobacillus composti sp. nov., a moderately thermophilic bacterium isolated from a composting reactor . In: International Journal of Systematic and Evolutionary Microbiology. Volume 57, 2007, pp. 1473-1477, doi : 10.1099 / ijs.0.64672-0
  3. ↑ JP Touzel, M. O'Donohue, P. Debeire, E. Samain and C. Breton: Thermobacillus xylanilyticus gen. Nov., Sp. nov., a new aerobic thermophilic xylan-degrading bacterium isolated from farm soil. In: International Journal of Systematic and Evolutionary Microbiology. Volume 50, 2000, pp. 315-320, doi : 10.1099 / 00207713-50-1-315

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 .