Beggiatoa
Encyclopedia
Beggiatoa is a genus
of bacteria in the order Thiotrichales
. They are named after the Italian medic and botanist F.S. Beggiato. The organisms live in sulfur-rich environments. During his research in Anton de Bary
’s laboratory of botany in 1887, Russian botanist Sergei Winogradsky
found that Beggiatoa oxidized hydrogen sulfide
(H2S) as an energy source, forming intracellular sulfur
droplets. Winogradsky referred to this form of metabolism as inorgoxidation (oxidation of inorganic compounds). The finding represented the first discovery of lithotroph
y.
s, sulfur springs, sewage contaminated water, mud layers of lakes, and near deep hydrothermal vents. Beggiatoa can also be found in the rhizosphere
of swamp plants.
with a cell diameter that can measure between 12 to 160 micrometres (different subspecies). A massive central vacuole is used for accumulation of nitrate, presumably for use as an electron acceptor in anaerobic sulfide oxidation. The filaments are surrounded by slime and can move by gliding.
by oxidizing organic compounds to carbon dioxide in the presence of oxygen, although high concentrations of oxygen can be a limiting factor. Organic compounds are also the carbon source for biosynthesis
. Some species may oxidize hydrogen sulfide
to elemental sulfur
as a supplemental source of energy (facultatively litho-heterotroph). Produced sulfur is stored intracellular
ly.
Some species have the ability of chemolitho-autotrophic
growth by means of sulfide oxidation for energy and with carbon dioxide as a source of carbon for biosynthesis. In this metabolism internal stored nitrate is the electron acceptor and reduced to ammonia.
Marine autotrophic Beggiatoa species are able to oxidize intracellular sulfur to sulfate.
A frequently occurring mechanism when oxygen is lacking is reduction of elemental sulfur. Sulfur is reduced to sulfide at the cost of stored carbon or by added hydrogen gas. This may be a survival strategy to bridge periods without oxygen.
Filaments have been observed to form dense mats on sediments in estuarine, shelf, seep, and deep-sea hydrothermal vent environments. They appear as a whitish layer and since they are present and flourish in marine
environments which have been subject to pollution
, they can be considered as an indicator species
.
Beggiatoa and other related filamentous bacteria can cause settling problems in sewage treatment plants, industrial waste lagoons in canning, paper pulping, brewing, milling, causing the phenomenon called "bulking". Beggiatoa are also able to detoxify hydrogen sulfide in soil.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of bacteria in the order Thiotrichales
Thiotrichales
The Thiotrichales are an order of proteobacteria, including most notably Thiomargarita namibiensis, the largest known bacterium.They also include certain pathogens, such as Francisella tularensis which causes Tularemia ....
. They are named after the Italian medic and botanist F.S. Beggiato. The organisms live in sulfur-rich environments. During his research in Anton de Bary
Anton de Bary
Heinrich Anton de Bary was a German surgeon, botanist, microbiologist, and mycologist ....
’s laboratory of botany in 1887, Russian botanist Sergei Winogradsky
Sergei Winogradsky
Sergei Nikolaievich Winogradsky was a Ukrainian-Russian microbiologist, ecologist and soil scientist who pioneered the cycle of life concept. He discovered the first known form of lithotrophy during his research with Beggiatoa in 1887...
found that Beggiatoa oxidized hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
(H2S) as an energy source, forming intracellular sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
droplets. Winogradsky referred to this form of metabolism as inorgoxidation (oxidation of inorganic compounds). The finding represented the first discovery of lithotroph
Lithotroph
A lithotroph is an organism that uses an inorganic substrate to obtain reducing equivalents for use in biosynthesis or energy conservation via aerobic or anaerobic respiration. Known chemolithotrophs are exclusively microbes; No known macrofauna possesses the ability to utilize inorganic...
y.
Habitat
Beggiatoa can be found in marine or freshwater environments. They can usually be found in habitats that have high levels of hydrogen sulfide. These environments include cold seepCold seep
A cold seep is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool...
s, sulfur springs, sewage contaminated water, mud layers of lakes, and near deep hydrothermal vents. Beggiatoa can also be found in the rhizosphere
Rhizosphere (ecology)
The rhizosphere is the narrow region of soil that is directly influenced by root secretions and associated soil microorganisms. Soil which is not part of the rhizosphere is known as bulk soil. The rhizosphere contains many bacteria that feed on sloughed-off plant cells, termed rhizodeposition, and...
of swamp plants.
Morphology
The colorless cells are disk-shaped or cylindrical, arranged in long filamentsFilamentation
Filamentation is the anomalous growth of certain bacteria, such as E. coli, in which cells continue to elongate but do not divide . Bacterial filamentation is often observed as a result of bacteria responding to various stresses, including DNA damage or inhibition of replication...
with a cell diameter that can measure between 12 to 160 micrometres (different subspecies). A massive central vacuole is used for accumulation of nitrate, presumably for use as an electron acceptor in anaerobic sulfide oxidation. The filaments are surrounded by slime and can move by gliding.
Metabolism
Beggiatoa can grow chemoorgano-heterotrophicallyPrimary nutritional groups
Primary nutritional groups are groups of organisms, divided according to the sources of energy and carbon, needed for living, growth and reproduction...
by oxidizing organic compounds to carbon dioxide in the presence of oxygen, although high concentrations of oxygen can be a limiting factor. Organic compounds are also the carbon source for biosynthesis
Biosynthesis
Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...
. Some species may oxidize hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
to elemental sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
as a supplemental source of energy (facultatively litho-heterotroph). Produced sulfur is stored intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
ly.
Some species have the ability of chemolitho-autotrophic
Chemotroph
Chemotrophs are organisms that obtain energy by the oxidation of electron donors in their environments. These molecules can be organic or inorganic . The chemotroph designation is in contrast to phototrophs, which utilize solar energy...
growth by means of sulfide oxidation for energy and with carbon dioxide as a source of carbon for biosynthesis. In this metabolism internal stored nitrate is the electron acceptor and reduced to ammonia.
-
- Sulfide oxidation: 2H2S + O2 → 2S + 2H2O
Marine autotrophic Beggiatoa species are able to oxidize intracellular sulfur to sulfate.
A frequently occurring mechanism when oxygen is lacking is reduction of elemental sulfur. Sulfur is reduced to sulfide at the cost of stored carbon or by added hydrogen gas. This may be a survival strategy to bridge periods without oxygen.
Ecology
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
environments which have been subject to pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
, they can be considered as an indicator species
Indicator species
An indicator species is any biological species that defines a trait or characteristic of the environment. For example, a species may delineate an ecoregion or indicate an environmental condition such as a disease outbreak, pollution, species competition or climate change...
.
Beggiatoa and other related filamentous bacteria can cause settling problems in sewage treatment plants, industrial waste lagoons in canning, paper pulping, brewing, milling, causing the phenomenon called "bulking". Beggiatoa are also able to detoxify hydrogen sulfide in soil.