Modulibacteria(Moduliflexota) is a
bacterial phylum formerly known as KS3B3 or GN06. It is a
candidate
A candidate, or nominee, is a prospective recipient of an award or honor, or a person seeking or being considered for some kind of position. For example, one can be a candidate for membership in a group (sociology), group or election to an offic ...
phylum, meaning there are no cultured representatives of this group. Members of the Modulibacteria phylum are known to cause fatal filament overgrowth (bulking) in high-rate industrial
anaerobic
Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to:
*Adhesive#Anaerobic, Anaerobic ad ...
wastewater treatment
bioreactor
A bioreactor is any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical reaction, chemical process is carried out which involves organisms or biochemistry, biochem ...
s.
The Modulibacteria phylum was first proposed in 2006 by two independent research groups based on analyses of
16S rRNA
16S ribosomal RNA (or 16Svedberg, S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure.
The genes coding for it are referred to as ...
gene sequences. One group recovered Modulibacteria sequences from the a
hypersaline
A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing those of ocean water (3.5%, i.e. ).
Specific microbial species can thrive i ...
microbial mat from
Guerrero Negro
Guerrero Negro (English: Black Warrior) is the largest town located in the municipality of Mulegé in the Mexican state of Baja California Sur (BCS). It had a population of 13,596 in the 2020 census. The town is served by Guerrero Negro Airport. ...
(Baja California Sur, Mexico) and used the provisional name GN06 for the novel
phylum
In biology, a phylum (; : phyla) is a level of classification, or taxonomic rank, that is below Kingdom (biology), kingdom and above Class (biology), class. Traditionally, in botany the term division (taxonomy), division has been used instead ...
, while the other recovered sequences from sulfur-rich black mud
marine sediments
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor. These particles either have their origins in soil and rocks and have been transported from the land to the sea ...
(CA, USA) and used the provisional name KSB3.
The first
genomic
Genomics is an interdisciplinary field of molecular biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, ...
insights into the phylum were achieved in 2015, at which time the name "Modulibacteria" was proposed.
Two genomes were recovered from
methanogenic
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. It is the fourth and final stage of anaerobic digestion. Organisms capable of producing methane for energy conservation h ...
sludge samples of a full-scale
upflow anaerobic sludge blanket (UASB) reactor treating a high-strength organic
wastewater
Wastewater (or waste water) is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of do ...
discharged from a food-processing factory.
Through a combination of genome-based
metabolic
Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the ...
reconstruction and microscopic observation, it was determined that the two studied Modulibacteria species (''Moduliflexus flocculans'' and ''Vecturithrix granuli'') produce filamentous structures and are
Gram-negative
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...
, strictly anaerobic
fermenter
Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chem ...
s capable of non-
flagellar based gliding motility. Both have an unusually large number of sensory and response
regulator gene
In genetics, a regulator gene, regulator, or regulatory gene is a gene involved in controlling the expression of one or more other genes. Regulatory sequences, which encode regulatory genes, are often at the five prime end (5') to the start si ...
s compared to other bacteria.
Members of the Modulibacteria phylum have been detected in a variety of environments in addition to bioreactors and hypersaline mats, such as wetland sediments
FJ516883.1, the
dolphin
A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...
mouth, and a
tubeworm from a
coldseepFM165273.
Taxonomy
The following taxonomy was proposed by Sekiguchi et al. 2015
and phylogeny by
GTDB
The Genome Taxonomy Database (GTDB) is an online database that maintains information on a proposed nomenclature of prokaryotes, following a phylogenomic approach based on a set of conserved single-copy proteins. In addition to resolving paraphyl ...
08-RS214
* Class "Moduliflexia"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturitrichia" Sekiguchi et al. 2015** Order "Moduliflexales"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturatrichales" Sekiguchi et al. 2015*** Family "Moduliflexaceae"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturatrichaceae" Sekiguchi et al. 2015**** Genus "''Candidatus''
Moduliflexus"
Sekiguchi et al. 2015
***** Species "''Ca.'' M. flocculans"
Sekiguchi et al. 2015
**** Genus "''Candidatus''
Vecturithrix"
Sekiguchi et al. 2015
***** Species "''Ca.'' V. granuli"
Sekiguchi et al. 2015
See also
*
List of bacteria genera
This article lists the genera of the bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, ...
*
List of bacterial orders
This article lists the orders of the Bacteria. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI)
and the phylogeny is based on 16 ...
References
{{Taxonbar, from=Q27067426
Bacteria phyla
Candidatus taxa