Sphaerotilus natans
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Sphaerotilus natans in a wastewater contaminated river |
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| Sphaerotilus natans | ||||||||||||
| Kützing , 1833 |
Sphaerotilus natans is a bacterium - type from the genus Sphaerotilus . They are rod-shaped bacteria which, as a special feature, form thin-walled tubes in which they are arranged one behind the other. They occur in slowly flowing waters, ditches and ponds that have a high content of biodegradable substances. Because masses of these bacteria look macroscopically like a mycelium due to their arrangement in long tubes and occur in connection with wastewater, this type of bacteria is also called wastewater fungus . However, communities of different thread-forming bacteria are also referred to as wastewater fungus in which S. natans is an essential component.
properties
Straight, rod-shaped (generally cylindrical) cell , diameter 1.2-2.5 microns, microns in length 1-10, gram-negative , occasionally respectively at a cell end subpolar a flagellar (polytrich, mono polar flagella). The bacteria swim freely ("swarmers"), but mostly they form longitudinal rows (single-row cell chains), which are located in a thin-walled tube made of biological material that is separated from them. These tubes, also known as sheaths (similar to sheaths for edged weapons), are made of biopolymers that form intertwined fibrils and are smooth on the outside. They consist of 36–54% carbohydrates , 12–28% proteins and 1–5% lipids . The cells are not firmly attached to the tubes and can move around in them. One end of the sheaths can be pinned to solid surfaces. Mucus is sometimes deposited outside the vagina. With high concentrations of bio-organic substances in the medium, growth and multiplication can occur without shedding. As a reserve substance is polyhydroxybutyric acid formed, and in the form of granules deposited in the cells. The GC content of the DNA is 68-71 mol%. Rest stages are not known.
metabolism
The energy metabolism is strictly aerobic , oxidative , chemoorganoheterotrophic . Several different bio- organic substances are used (including polysaccharides , simple carbohydrates , some alcohols , amino acids , butyric acid and other organic acids ). Glucose is broken down via the phosphogluconate pathway and citric acid cycle . As nitrogen sources, amino acids and ammonium - and nitrate - ions used. Vitamin B12 is needed. S. natans grows well even with low oxygen concentrations in the medium .
Occurrence, ecology
S. natans occurs in slowly flowing waters, ditches and ponds that have a high content of bio-organic substances, especially in urban sewage, agricultural sewage, sewage from factories in which paper or agricultural products (potatoes, milk, etc.) are manufactured or processed as well as their cleaning systems and in waters that are polluted with such wastewater. The pH range of growth is 5.4–9.0, the pH optimum is 6.5–7.6, the temperature range of growth is 10–40 ° C, the temperature optimum is 20–30 ° C, Salt tolerance of growth up to 3–7 g / L sodium chloride (NaCl).
Sheathing the bacterial cells with sheaths has the advantage that filaments are formed in this way without the need for cell lengthening or the formation of multicellular cell threads. Filaments cause a loose, surface-rich aggregation , which favors the exchange of substances with the surrounding medium. At the same time, the vagina protects the bacteria from bacteria-eating organisms (especially protozoa ) and from bacteriophages . The attachment to solid surfaces offers the advantage in flowing waters that new nutrients are constantly brought in and metabolic products are washed away.
Technical importance
In wastewater treatment plants , Sphaerotilus natans causes the so-called bulking sludge , a mass of microorganisms that floats in the aqueous medium and does not or only extremely slowly sediment through the formation of masses of long, thread-like sheaths together with other thread-forming bacteria ( e.g. Haliscomenobacter ) . This prevents the technically necessary separation of the microorganisms and disrupts the operation of the wastewater treatment plants. The bulking sludge formation also leads to clogging of systems in bodies of water.
This damage underneath a sugar factory plays an important role in the novel Pfister's mill ("Abwasserroman") by Wilhelm Raabe . The bacterium is not named by its name, but the typical shaggy bacterial masses in the water and on a mill wheel are described. The story is based on a real case of water pollution by waste water from the Rautheim sugar factory near Braunschweig, in which the botanist and microbiologist Ferdinand Cohn was involved as an expert.
Individual evidence
- ↑ a b c d e f g h i j John G. Holt, Noel R. Krieg, Peter HA Sneath, James T. Staley, Stanley T. Williams: Bergey's Manual of determinative bacteriology. 9th ed. Williams and Wilkins, Baltimore et al. O. 1994, ISBN 0-683-00603-7 , pp. 480-482.
- ↑ a b c d e f g h i j k l m n o p q r Stefan Spring: The genera Leptothrix and Sphaerotilus. In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer , Erko Stackebrandt (eds.): The Prokaryotes. 3rd Edition, Vol. 5, pp. 758-777. Springer, New York et al. O. 2006, ISBN 978-0-387-25495-1 .
- ↑ Horst Denkler : Afterword. In: Wilhelm Raabe: Pfisters Mühle - A summer vacation booklet . Reclam's Universal Library 9988, Reclam, Ditzingen 1996, ISBN 978-3-15-009988-9 , pp. 233-235.
- ↑ Horst Denkler: Afterword. In: Wilhelm Raabe: Pfisters Mühle - A summer vacation booklet . Reclam's Universal Library 9988, Reclam, Ditzingen 1996, ISBN 978-3-15-009988-9 , p. 228.
- ↑ Comment on p. 94, line 29 in the appendix to Wilhelm Raabe: Pfisters Mühle - Ein Sommerferienheft . Reclam's Universal Library 9988, Reclam, Ditzingen 1996, ISBN 978-3-15-009988-9 .
literature
- FT Kützing: Contribution to the knowledge about the formation and metamorphosis of the lower vegetable organisms, together with a systematic compilation of the lower algae forms belonging here . In: Linnaea . Vol. 8, 1833, pp. 335-387.
- EG Mulder, WL van Veen: Investigations on the Sphaerotilus-Leptothrix group . In: Antonie van Leeuwenhoek Journal of Microbiology and Serology . Vol. 29, 1963, pp. 121-153.
- Véronique Pellegrin, Stefan Juretschko, Michael Wagner , Gilles Cottenceau1: Morphological and biochemical properties of a Sphaerotilus sp. isolated from paper mill slimes. In: Applied and Environmental Microbiology . Vol. 65, Issue 1, 1999, pp. 156-162.
- Stefan Spring: The genera Leptothrix and Sphaerotilus . In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes . 3rd Edition, Vol. 5, pp. 758-777. Springer, New York et al. O. 2006, ISBN 978-0-387-25495-1 .
- George M. Garrity, Julia A. Bell, Timothy G. Lilburn: Taxonomic Outline of the Prokaryotes. Bergey's Manual of Systematic Bacteriology . Second Edition, Release 5.0, Springer-Verlag, New York, 2004. doi : 10.1007 / bergeysoutline200310 PDF .
- Wilhelm Raabe: Pfisters Mühle - A summer vacation booklet . Story, novel. First published in: Die Grenzboten - magazine for politics, literature and art . Leipzig 1884. Modern edition including: Reclams Universal-Bibliothek 9988, Reclam, Ditzingen 1996, ISBN 978-3-15-009988-9 .
