Geobacillus stearothermophilus

from Wikipedia, the free encyclopedia
Geobacillus stearothermophilus
Systematics
Department : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Bacillaceae
Genre : Geobacillus
Type : Geobacillus stearothermophilus
Scientific name
Geobacillus stearothermophilus
(Donk 1920) Nazina et al. 2001 emend. Coorevits et al. 2012

Geobacillus stearothermophilus (until 2001 classified as Bacillus stearothermophilus ) is a spore-forming, gram - positive rod-shaped bacterium .

The cells have an average diameter of 0.6-1 µm and a length between 2 and 3.5 µm. The optimal growth temperature is between 50 and 65 ° C, making Geobacillus stearothermophilus one of the thermophilic organisms. At temperatures below 30 ° C, the cells no longer grow.

The formation of the endospores takes place terminally, during which the bacterial cell is expanded in the shape of a club. The resistant spores are found in soils, in hot springs, in desert sand, in arctic waters, in the seabed, in food and in compost, but germinate only under favorable conditions. The bacterium is not pathogenic for humans or animals, i.e. it is not pathogenic.

Geobacillus stearothermophilus serves as a test germ for the success of thermal sterilization processes ( e.g. autoclaving ). For this purpose, glass ampoules are used, for example, which contain a liquid nutrient medium , spores of Geobacillus stearothermophilus and a color indicator. The ampoules are autoclaved as usual and then incubated together with a non-autoclaved control ampoule at about 60 ° C. for several days. The metabolic activity of the cells is indicated by a color change in the indicator. Successfully sterilized ampoules therefore do not change their color. Another form of application are spore strips, which are filter paper strips on which the endospores have been applied. To check the steam sterilization, the spore strips are placed in the autoclave, then they are placed in a nutrient solution and incubated as indicated above. If the sterilization is successful, no growth occurs.

Geobacillus stearothermophilus is used to generate the enzyme BstBI .

Individual evidence

  1. ↑ Catalog of microorganisms. Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, accessed on February 17, 2013 (English).
  2. ↑ Michael T. Madigan, John M. Martinko, Jack Parker: Brock Microbiology. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 978-3-8274-0566-1
  3. ^ A b Hans G. Schlegel: General microbiology. 7th edition. Thieme Verlag, Stuttgart / New York 1992, ISBN 3-13-444607-3
  4. ↑ a b Eckhard Bast: Microbiological Methods: An Introduction to Basic Working Techniques. 2nd Edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2001, ISBN 978-3-8274-1072-6