color = lightgrey
name = Hyphomicrobiaceae
regnum = Bacteria
classis = Alpha Proteobacteria
familia = Hyphomicrobiaceae
subdivision_ranks = Genera
subdivision = "
Pedomicrobium is a ubiquitous bacterium dominant in
biofilmsof man-made aquatic environments such as water distribution systems and bioreactors. Due to their abilities to oxidise manganese(Mn), they are found to be the main culprits of Mn related “dirty water” (Sly et al., 1988a).
Taxonomy and Ecology of Pedomicrobium
Based on 16S rRNA sequence analysis, Pedomicrobium is a bacterium that belongs to the family
Hyphomicrobiaceae, within the order of Rhizobialesunder the class of alphaproteobacteria, in the phylum Proteobacteria(Garrity et al., 2001). There are twenty genera belonging to the Hyphomicrobiaceae family (Williams et al, 1990), of which Pedomicrobium is most closely related to Hyphomicrobiumand Filomicrobium(Stahl et al., 1992).
The genus Pedomicrobium consists of three species, with Mn oxidizing and accumulating species represented by Pedomicrobium manganicum and Pedomicrobium americanum, whilst the species Pedomicrobium ferrugineum oxidizes iron but not Mn (Cox and Sly, 1997).
budding hyphalbacteria that can be found in both terrestrial and aquatic environments (Sly et al., 1988a). The dimorphic mode of reproduction results in a non-motile form, which has the ability to adhere strongly to surfaces and form biofilm (Sly et al., 1988b). The attached cells take advantage of the nutrients and soluble manganous ions attracted to the solid-liquid interface, which are continually replenished by the water flow (Sly et al., 1988a). Mn oxidising bacteria in biofilms have been shown to greatly enhance the rate of Mn oxidation (Sly et al., 1988b).
Oxidation of Manganese by Pedomicrobium
The association of Mn oxides with the surfaces of microbial cells is well known (Larsen et al., 1999). Oxidation of Mn by Pedomicrobium has been shown to occur enzymatically, and the deposition of the manganous oxide occurs on extracellular acidic polysaccharides (Sly et al., 1990a; Larsen et al., 1999). The mechanism of Mn II oxidation by Pedomicrobium is a two-step process involving adsorption of Mn through surface charges and ionic attraction, and subsequent oxidation to Mn oxide (Larsen et al., 1999). Larsen et al. (1999) showed that the Mn oxidising enzyme was located in the outer cell membranes and that enzyme activity was copper-dependent. Recent research in the laboratory has shown that the gene encoding the Mn oxidising enzyme is a putative
multicopper oxidasewith four copper binding sites.
Effects of Manganese
Mn is considered a secondary
contaminant, which includes substances in water that cause offensive taste, odour, colour, corrosion, foaming, or staining but have no direct affect on health (Herman, 1996). In fact, small concentrations of Mn in our diet are essential to human health (Keen et al., 1999).
Therefore Mn is regarded as a nuisance metal in water distribution systems as in the insoluble oxide form it reduces the aesthetic quality of the water. The presence of Mn results in the accumulation of metal oxides in biofilm on the surfaces of water mains, which may slough off resulting in brown-black colour and turbidity that are characteristics of Mn related dirty water (Sly et al., 1990b). The sediments produced are responsible for the taste and staining properties of water, which commonly affects laundry, porcelain, dishes, utensils and swimming pools (Vaner et al., 1996).
Cox T. L, and Sly L. I; (1997); ‘Phylogenetic relationships and uncertain taxonomy of Pedomicrobium species’; International Journal of Systematic Bacteriology 47(2):377-380.
Garrity G. M., Winters M. and Searles D. B.; (2001); ‘Taxonomic outline of the procaryotic genera Bergey’s manual of systematic bacteriology, Second Edition Release 1.0.
Keen C. L., Ensunsa J. L. and Watson M. H.; (1999); ‘Nutritional aspects of manganese from experimental studies’; Neurotoxicology 20:213-23.
Larsen E. I., Sly L. I. and McEwan A. G.; (1999); ‘Manganese(II) adsorption and oxidation by whole cells and a membrane fraction of Pedomicrobium sp. ACM 3067’; Archives of Microbiology 171:257-264.
Sly L. I.; Arunpairojana V. and Hodgkinson M. C.; (1988a); ‘Pedomicrobium manganicum from drinking-water distribution systems with manganese-related “dirty water” problems’; Systematic and Applied Microbiology 11:75-84.
Sly L. I., Hodgkinson M. C. and Arunpairojana, V; (1988b); ‘Effect of water velocity ion the early development of manganese depositing biofilm in a drinking water system’; FEMS Microbiology ecology 53:175-186.
Sly L. I., Hodgkinson M. C. and Arunpairojana, V; (1988c); ‘The importance of high aesthetic potable water in tourist and recreational areas’; Water Science Technology 21:183-187.
Stahl D. A., Key R., Flesher B., and Smit J.; (1992); ‘The phylogeny of marine and freshwater Caulobacter reflects their habitat’; Journal of Bacteriology 174:2193-2198.
Vaner D., Skipton S., Hay, D. and Jasa P.; (1996); ‘Drinking water: recommended practices to manage iron and manganese in a domestic water supply’; Water Resource Management 96(12):80-86.
Wikimedia Foundation. 2010.
Look at other dictionaries:
Порядок почкующиеся бактерии (Hyphomicrobiales) — К порядку почкующихся бактерий (Hyphomicrobiales) относятся гетеротрофные грамотрицательные неспорообразующие бактерии со своеобразной морфологией. Их характерной особенностью является наличие гиф выростов, образованных клеточной стенкой… … Биологическая энциклопедия
Hyphomicrobiaceae — Taxobox color = lightgrey name = Hyphomicrobiaceae regnum = Bacteria phylum = Proteobacteria classis = Alpha Proteobacteria ordo = Rhizobiales familia = Hyphomicrobiaceae subdivision ranks = Genera subdivision = Ancalomicrobium Ancylobacter… … Wikipedia
Prosthecate bacteria — are a non phylogenetically related group of Gram negative bacteria that possess appendages, termed prosthecae . These cellular appendages are neither pili nor flagella, as they are extensions of the cellular membrane and contain cytosol.cite book … Wikipedia
List of Bacteria genera — This article lists the genera of the Bacteria. =Phylum Acidobacteria . [cite journal |author=Barns SM, Cain EC, Sommerville L, Kuske CR |title=Acidobacteria phylum sequences in uranium contaminated subsurface sediments greatly expand the known… … Wikipedia
Hyphomicrobiaceae — Hyphomicrobiaceae Clasificación científica Dominio: Bacter … Wikipedia Español
Систематика прокариот — Содержание 1 Систематика Архей 2 Систематика Эубактерий 3 См. также … Википедия
Enteisenung und Entmanganung — Belüftungsbecken zur Enteisenung und Entmanganung Enteisenung und Entmanganung wird in der Wasserchemie die Entfernung von 2 wertigen Verbindungen des Eisens und des Mangans aus einem Wasser genannt. Normale Oberflächenwasser enthalten … Deutsch Wikipedia