Fervidobacterium islandicum | |
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Scientific classification | |
Domain: | |
Phylum: | |
Class: | |
Order: | |
Family: | Thermotogaceae
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Genus: | Fervidobacterium
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Species: | F. islandicum
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Binomial name | |
Fervidobacterium islandicum Huber et al. 1991
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Fervidobacterium islandicum is a species of extremely thermophilic anaerobic bacteria, first isolated from an Icelandic hot spring.
F. islandicum cells are Gram-negative motile rods, about 1.8 μm in length, and 0.6 μm in width occurring singly or in pairs.[1] About 50% of cells form large spheroids at one end known as a 'toga' commonly found in members of the phylum Thermotogota (formerly Thermotogae)[2]
F. islandicum isolate H21 grows in a pH range from 6.0 to 8.0 with an optimum at around 7.2.[1] Growth is observed at a temperature range between 40 °C and 80 °C, with an optimum of 70 °C.[3] At a temperature of 65 °C, strain H21 has a doubling time of 150 minutes.[1]
Growth of isolate H21 requires low amounts (0.3%) of yeast extract. When this is used as a single carbon and energy source, the final cell concentration is 1x107 cells/ml.[1] Growth is strongly enhanced by the addition of 0.2% pyruvate, ribose, glucose, maltose, raffinose, starch and, less efficiently, cellulose. Final cell concentrations with these additions can range from 2 to 5x108.[1] In the presence of glucose, F. islandicum produces the following end products: L(+) lactate, acetate, ethanol, H2 and CO2.[1] Isolate H21 shows a sensitivity to common antibiotics, its growth is inhibited by addition of vancomycin, streptomycin, ampicillin, chloramphenicol and rifampicin at 10 g/ml.[1]
F. islandicum strain AW-1 has a total genome size of 2.4 million base pairs, which is slightly larger than the genomes of other Fervidobacterium strains.[3] It has a G + C content of 40.7%.[3] It contains 2,184 protein coding genes in a total of 2,248 genes.[3]
F. islandicum was originally isolated from an Icelandic hot spring on the banks of the river Varma close to Hverageri, Iceland. The anaerobic samples were taken from hot waters and muds.[1] Here, the temperatures were between 70 °C and 102 °C, and the pH was between 1.5 and 9.[1]
F. islandicum AW-1 is capable of complete feather degradation at 70 °C and a pH of 7.[4] Feather keratin has a very high cysteine content, which makes it very rigid and hard to digest.[5] 5 million tons of chicken feathers are generated by the poultry industry every year, making chicken feathers a serious solid waste problem.[4] Therefore, F. islandicum's ability to degrade native chicken feathers is very appealing.[citation needed]