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{{short description|Species of bacterium}}
{{Taxobox
{{Taxobox
| color = lightgrey
| image = R. palustric bacteria.png
| image = R. palustric bacteria.png
| image_width = 250px
| image_width = 250px
| domain = [[Bacteria]]
| domain = [[Bacteria]]
| phylum = [[Proteobacteria]]
| phylum = [[Pseudomonadota]]
| classis = [[Proteobacteria|Alphaproteobacteria]]
| classis = [[Alphaproteobacteria]]
| ordo = [[Rhizobiales]]
| ordo = [[Hyphomicrobiales]]
| familia = [[Bradyrhizobiaceae]]
| familia = [[Nitrobacteraceae]]
| genus = ''[[Rhodopseudomonas]]''
| genus = ''[[Rhodopseudomonas]]''
| species = '''''R. palustris'''''
| species = '''''R. palustris'''''
Line 13: Line 13:
| binomial_authority = (Molisch 1907) van Niel 1944
| binomial_authority = (Molisch 1907) van Niel 1944
| synonyms = * ''Rhodopseudomonas rutila'' <small>Akiba ''et al''. 1983</small>
| synonyms = * ''Rhodopseudomonas rutila'' <small>Akiba ''et al''. 1983</small>
| synonyms_ref = <ref>{{cite journal|doi=10.1099/00207713-42-1-186|title=Rhodopseudomonas rutila is a Later Subjective Synonym of Rhodopseudomonas palustris|journal=International Journal of Systematic Bacteriology|volume=42|pages=186|year=1992|last1=Hiraishi|first1=A.|last2=Santos|first2=T. S.|last3=Sugiyama|first3=J.|last4=Komagata|first4=K.}}</ref>
| synonyms_ref = <ref>{{cite journal | vauthors = Hiraishi A, Santos TS, Sugiyama J, Komagata K |title=Rhodopseudomonas rutila is a Later Subjective Synonym of Rhodopseudomonas palustris |journal=International Journal of Systematic Bacteriology |volume=42 |pages=186–188 |year=1992 |doi=10.1099/00207713-42-1-186 |doi-access=free}}</ref>
}}
}}


'''''Rhodopseudomonas palustris''''' is a [[bacillus|rod-shaped]] [[gram-negative]] [[purple non-sulfur bacteria|purple non-sulfur bacterium]], notable for its ability to switch between four different modes of metabolism.<ref name=larimer>{{cite journal
'''''Rhodopseudomonas palustris''''' is a [[bacillus|rod-shaped]], [[Gram-negative]] [[purple non-sulfur bacteria|purple nonsulfur bacterium]], notable for its ability to switch between four different modes of metabolism.<ref name=larimer>{{cite journal | vauthors = Larimer FW, Chain P, Hauser L, Lamerdin J, Malfatti S, Do L, Land ML, Pelletier DA, Beatty JT, Lang AS, Tabita FR, Gibson JL, Hanson TE, Bobst C, Torres JL, Peres C, Harrison FH, Gibson J, Harwood CS | display-authors = 6 | title = Complete genome sequence of the metabolically versatile photosynthetic bacterium Rhodopseudomonas palustris | journal = Nature Biotechnology | volume = 22 | issue = 1 | pages = 55–61 | date = January 2004 | pmid = 14704707 | doi = 10.1038/nbt923 | doi-access = free }}</ref>
| title=Complete genome sequence of the metabolically versatile photosynthetic bacterium ''Rhodopseudomonas palustris''
| journal=Nature Biotechnology
| volume=22
| year=2004
| issue=1
| pages=55–61
| doi=10.1038/nbt923
| url=http://www.nature.com/nbt/journal/v22/n1/full/nbt923.html
| pmid=14704707
| author1=Larimer
| first1=F. W.
| last2=Chain
| first2=P
| last3=Hauser
| first3=L
| last4=Lamerdin
| first4=J
| last5=Malfatti
| first5=S
| last6=Do
| first6=L
| last7=Land
| first7=M. L.
| last8=Pelletier
| first8=D. A.
| last9=Beatty
| first9=J. T.
| last10=Lang
| first10=A. S.
| last11=Tabita
| first11=F. R.
| last12=Gibson
| first12=J. L.
| last13=Hanson
| first13=T. E.
| last14=Bobst
| first14=C
| last15=Torres
| first15=J. L.
| last16=Peres
| first16=C
| last17=Harrison
| first17=F. H.
| last18=Gibson
| first18=J
| last19=Harwood
| first19=C. S.
}}</ref>


''R. palustris'' is found extensively in nature and has been isolated from swine waste lagoons, earthworm droppings, marine coastal sediments and pond water. Although purple non-sulfur bacteria are normally [[photoheterotrophic]], ''R. palustris'' can flexibly switch among any of the four modes of metabolism that support life: [[photoautotrophic]], photoheterotrophic, [[chemoautotrophic]] and [[chemotroph|chemoheterotrophic]].<ref name="larimer"/>
''R. palustris'' is found extensively in nature, and has been isolated from swine waste lagoons, earthworm droppings, marine coastal sediments, and pond water. Although purple nonsulfur bacteria are normally [[photoheterotrophic]], ''R. palustris'' can flexibly switch among any of the four modes of metabolism that support life: [[photoautotrophic]], [[photoheterotroph]]ic, [[chemoautotrophic]], or [[chemotroph|chemoheterotrophic]].<ref name="larimer"/>


==Etymology==
==Etymology==


''R. palustris'' is usually found as a wad of slimy masses and cultures appear from pale brown to peach-colored. Etymologically, ''rhodum'' is a Greek noun meaning rose, ''pseudes'' is the Greek adjective for false and ''monas'' refers to a unit in Greek. Therefore, ''Rhodopseudomonas'', which implies a unit of false rose, describes the appearance of the bacteria. ''Palustris'' is Latin for marshy, and indicates the common habitat of the bacterium.<ref> Archibald William Smith {{google books|ahNMkgoNJ7IC|A Gardener's Handbook of Plant Names: Their Meanings and Origins|page=258}}</ref>
''R. palustris'' is usually found as a wad of slimy masses, and cultures appear from pale brown to peach-colored. Etymologically, ''rhodum'' is a Greek noun meaning rose, ''pseudes'' is the Greek adjective for false, and ''monas'' refers to a unit in Greek. Therefore, ''Rhodopseudomonas'', which implies a unit of false rose, describes the appearance of the bacteria. ''Palustris'' is Latin for marshy, and indicates the common habitat of the bacterium.<ref>{{cite book | vauthors = Smith AW |title=A gardener's handbook of plant names: their meanings and origins |date=1997 |publisher=Dover Publications |location=Mineola, NY |isbn=978-0-486-29715-6 |page=258 |edition=Dover |url=https://books.google.com/books?id=ahNMkgoNJ7IC&pg=PA258 }}</ref>


==Modes of metabolism==
==Modes of metabolism==
<!-- Deleted image removed: [[File:R. palustris metabolism.gif|thumbnail|left|upright=2.0|This figure shows schematic diagrams of the four modes of metabolism that ''R. palustris'' can undergo. (Larimer et al. 2004){{deletable image-caption|Saturday, 14 June 2014}}]] -->
<!-- Deleted image removed: [[File:R. palustris metabolism.gif|thumbnail|left|upright=2.0|This figure shows schematic diagrams of the four modes of metabolism that ''R. palustris'' can undergo. (Larimer et al. 2004){{deletable image-caption|Saturday, 14 June 2014}}]] -->


''R. palustris'' can grow with or without [[oxygen]], or it can use light, inorganic or organic compounds for energy. It can also acquire [[carbon]] from either [[carbon fixation|carbon dioxide fixation]] or green plant-derived compounds. Finally, ''R. palustris'' is also capable of [[nitrogen fixation|fixing nitrogen]] for growth. This metabolic versatility has raised interest in the research community, and it makes this bacterium suitable for potential use in [[biotechnology|biotechnological]] applications.
''R. palustris'' can grow with or without [[oxygen]], or it can use light or inorganic or organic compounds for energy. It can also acquire [[carbon]] from either [[carbon fixation|carbon dioxide fixation]] or green plant-derived compounds. Finally, ''R. palustris'' is also capable of [[nitrogen fixation|fixing nitrogen]] for growth. This metabolic versatility has raised interest in the research community, and it makes this bacterium suitable for potential use in [[biotechnology|biotechnological]] applications.


Efforts are currently being made to understand how this organism adjusts its metabolism in response to environmental changes. The complete genome of the strain ''Rhodopseudomonas palustris'' CGA009 was sequenced in 2004 (see [[list of sequenced bacterial genomes]]) to get more information about how the bacterium senses environmental changes and regulates its metabolic pathways. It was found that ''R. palustris'' can deftly acquire and process various components from its environment, as necessitated by fluctuations in the levels of carbon, nitrogen, oxygen and light.
Efforts are currently being made to understand how this organism adjusts its metabolism in response to environmental changes. The complete genome of the strain ''Rhodopseudomonas palustris'' CGA009 was sequenced in 2004 (see [[list of sequenced bacterial genomes]]) to get more information about how the bacterium senses environmental changes and regulates its metabolic pathways. ''R. palustris'' can deftly acquire and process various components from its environment, as necessitated by fluctuations in the levels of carbon, nitrogen, oxygen, and light.


''R. palustris'' has genes that encode for proteins that make up [[light-harvesting complexes]] and photosynthetic reaction centres. LH complexes and photosynthetic reaction centers are typically found in photosynthetic organisms like green [[plants]]. Moreover, ''R. palustris'' can modulate [[photosynthesis]] according to the amount of light available, like other purple bacteria. For instance, in low-light circumstances, it responds by increasing the level of these LH complexes that allow light absorption. However, the wavelengths of the light absorbed by ''R. palustris'' differ from those absorbed by other phototrophs.
''R. palustris'' has genes that encode for proteins that make up [[light-harvesting complexes]] (LHCs) and photosynthetic reaction centers. LHCs and photosynthetic reaction centers are typically found in photosynthetic organisms such as green plants. Moreover, ''R. palustris'' can modulate [[photosynthesis]] according to the amount of light available, like other purple bacteria. For instance, in low-light circumstances, it responds by increasing the level of these LHCs that allow light absorption. The wavelengths of the light absorbed by ''R. palustris'' differ from those absorbed by other phototrophs.


''R. palustris'' also has [[genes]] that encode for the protein [[ruBisCO]], an enzyme that is necessary for [[carbon dioxide]] fixation in plants and other photosynthetic organisms. The genome of CGA009 also reveals the existence of proteins involved in [[nitrogen fixation]] (see [[diazotroph]]).
''R. palustris'' also has [[genes]] that encode for the protein [[ruBisCO]], an enzyme necessary for [[carbon dioxide]] fixation in plants and other photosynthetic organisms. The genome of CGA009 also reveals the existence of proteins involved in [[nitrogen fixation]] (see [[diazotroph]]).


In addition, this bacterium can combine oxygen-sensitive and oxygen-requiring enzyme reaction processes for metabolism and thus, it can thrive under varying and even very little levels of oxygen.
In addition, this bacterium can combine oxygen-sensitive and oxygen-requiring enzyme reaction processes for metabolism, thus it can thrive under varying and even very little levels of oxygen.


==Commercial applications==
==Commercial applications==
'''<big>BioFossil Fuel Industry</big>'''


''R. palustris'', during its photoautotrophic mode of metabolism possibly uses [[Vanabin]] to cleave the core out of [[Chlorin]] based compounds such as the [[Magnesium]] in [[Chlorophyll]] and replaces it with its [[Vanadium#:~:text=Vanadium is a chemical element,free metal against further oxidation.|Vanadium]] center in order to attach and harvest energy via [[Light-harvesting complex|Light Harvesting Complexes]] making ''R. Palustris'' a potential ingredient in the future of the fuel industry.
=== Agricultural Use ===
R. Palustris is commonly used in soil and soil-less agriculture under the brand name Rhiza Nova from Ameret. In both applications, it has been known to decrease water needed for irrigation up to 40% while increasing yields of a wide range of crops including rice and cannabis.


===Biodegradation===
===Biodegradation===
The genome of ''R. palustris'' consists of a variety of genes that are responsible for biodegradation. ''R. palustris'' can metabolize lignin and acids found in degrading plant and animal waste by metabolizing carbon dioxide. In addition, it can degrade [[aromatic]] compounds found in industrial waste. This bacterium is an efficient biodegradation catalyst in both aerobic and anaerobic environments.
The genome of ''R. palustris'' consists of a variety of genes that are responsible for biodegradation. It can metabolize lignin and acids found in degrading plant and animal waste by metabolizing carbon dioxide.<ref>{{cite journal | vauthors = Oshlag JZ, Ma Y, Morse K, Burger BT, Lemke RA, Karlen SD, Myers KS, Donohue TJ, Noguera DR | display-authors = 6 | title = Anaerobic Degradation of Syringic Acid by an Adapted Strain of Rhodopseudomonas palustris | language = EN | journal = Applied and Environmental Microbiology | volume = 86 | issue = 3 | date = January 2020 | pmid = 31732577 | pmc = 6974649 | doi = 10.1128/AEM.01888-19 }}</ref> In addition, it can degrade [[aromatic]] compounds found in industrial waste.<ref>{{cite journal |last1=Haq |first1=Irshad |last2=Christensen |first2=Annika |last3=Fixen |first3=Kathryn |title=Evolution of Rhodopseudomonas palustris to degrade halogenated aromatic compounds involves changes in pathway regulation and enzyme specificity |journal=Applied and Environmental Microbiology |date=11 January 2024 |volume=90 |issue=2 |pages=e02104-23 |doi=10.1128/aem.02104-23 |url=https://journals.asm.org/doi/10.1128/aem.02104-23 |access-date=15 March 2024|pmc=10880631 }}</ref> This bacterium is an efficient biodegradation catalyst in both aerobic and anaerobic environments. {{citation needed|date=February 2018}}


===Hydrogen production===
===Hydrogen production===
Purple phototrophic bacteria generate interest due to their biotechnological applications. These bacteria can be used for bioplastic synthesis and [[hydrogen]] production. ''R. palustris'' has the unique characteristic of encoding for a [[vanadium nitrogenase|vanadium-containing]] [[nitrogenase]]. It produces, as a byproduct of nitrogen fixation, three times more hydrogen than do molybdenum-containing nitrogenases of other bacteria.<ref name="larimer"/> The potential to manipulate ''R. palustris'' to be used as a reliable hydrogen production source or for biodegradation still lacks detailed knowledge of its metabolic pathways and regulation mechanisms.
Purple phototrophic bacteria have drawn interest for their biotechnological applications. These bacteria can be used for bioplastic synthesis and [[hydrogen]] production. ''R. palustris'' has the unique characteristic of encoding for a [[vanadium nitrogenase|vanadium-containing]] [[nitrogenase]]. It produces, as a byproduct of nitrogen fixation, three times more hydrogen than do molybdenum-containing nitrogenases of other bacteria.<ref name="larimer"/> The potential to manipulate ''R. palustris'' to be used as a reliable hydrogen production source or for biodegradation still lacks detailed knowledge of its metabolic pathways and regulation mechanisms.


===Electricity generation===
===Electricity generation===


====''Rhodopseudomonas palustris'' DX-1====
====''R. palustris'' DX-1====
A strain of ''R. palustris'' (DX-1) is one of the few [[microorganisms]] and the first ''Alphaproteobacteria'' found to generate electricity at high power densities in low-[[internal resistance]] [[microbial fuel cells]].<ref name=DX-1>{{cite journal
A strain of ''R. palustris'' (DX-1) is one of the few [[microorganisms]] and the first Alphaproteobacteria found to generate electricity at high power densities in low-[[internal resistance]] [[microbial fuel cells]] (MFCs).<ref name=DX-1>{{cite journal | vauthors = Xing D, Zuo Y, Cheng S, Regan JM, Logan BE | title = Electricity generation by Rhodopseudomonas palustris DX-1 | journal = Environmental Science & Technology | volume = 42 | issue = 11 | pages = 4146–4151 | date = June 2008 | pmid = 18589979 | doi = 10.1021/es800312v | bibcode = 2008EnST...42.4146X }}</ref> DX-1 produces electric current in MFCs in the absence of a catalyst, without light or hydrogen production. This strain is [[exoelectrogen]]ic, meaning that it can transfer electrons outside the cell. Other microorganisms isolated from MFCs cannot produce power densities higher than mixed cultures of microbes can under the same fuel-cell conditions, but ''R. palustris'' DX-1 can produce significantly higher power densities.


This ''Rhodopseudomonas'' species is widely found in wastewaters, and DX-1 generates electricity using compounds that ''Rhodopseudomonas'' is known to degrade. Therefore, this technology can be harnessed to produce bioelectricity from biomass and for wastewater treatment. However, the energy generated through this process is currently not sufficient for large-scale wastewater treatment.<ref name=mfc>{{cite journal | vauthors = Pant D, Van Bogaert G, Diels L, Vanbroekhoven K | title = A review of the substrates used in microbial fuel cells (MFCs) for sustainable energy production | journal = Bioresource Technology | volume = 101 | issue = 6 | pages = 1533–1543 | date = March 2010 | pmid = 19892549 | doi = 10.1016/j.biortech.2009.10.017 }}</ref>
| title=Electricity generation by ''Rhodopseudomonas palustris'' DX-1
| journal=Environmental Science & Technology
| volume=42
| year=2008
| issue=11
| pages=4146–4151
| doi=10.1021/es800312v
| pmid=18589979
| bibcode=2008EnST...42.4146X
| last3=Cheng
| first3=Shaoan
| last4=Regan
| first4=John M.
| last5=Logan
| first5=Bruce E.
| author1=Xing
| first1=D
| last2=Zuo
| first2=Y
}}</ref> DX-1 produces electric current in MFCs in the absence of a catalyst, without light or hydrogen production. This strain is [[exoelectrogen]]ic, meaning that it can transfer electrons outside the cell. Other microorganisms isolated from MFCs cannot produce power densities higher than mixed cultures of microbes can under the same fuel cell conditions. However, ''R. palustris'' DX-1 can produce significantly higher power densities.

The ''Rhodopseudomonas'' species is widely found in wastewaters, and DX-1 generates electricity using compounds that ''Rhodopseudomonas'' is known to degrade. Therefore, this technology can be harnessed to produce bioelectricity from biomass as well as for wastewater treatment. However, the energy generated through this process is currently not sufficient for large-scale wastewater treatment.<ref name=mfc>{{cite journal

| title=A review of the substrates used in microbial fuel cells (MFCs) for sustainable energy production
| journal=Bioresource Technology
| volume=101
| year=2010
| issue = 6
| pages=1533–1543
| doi=10.1016/j.biortech.2009.10.017
| url=http://www.sciencedirect.com/science/article/pii/S0960852409013595
| pmid=19892549
| author1=Pant
| first1=D
| last2=Van Bogaert
| first2=G
| last3=Diels
| first3=L
| last4=Vanbroekhoven
| first4=K
}}</ref>


====''Rhodopseudomonas palustris'' TIE-1====
====''Rhodopseudomonas palustris'' TIE-1====
A 2014 research explained the cellular processes that allow the strain ''R. palustris'' TIE-1 to obtain energy through [[extracellular electron transfer]].<ref name=TIE-1>{{cite journal
A 2014 study explained the cellular processes that allow the strain ''R. palustris'' TIE-1 to obtain energy through [[extracellular electron transfer]].<ref name=TIE-1>{{cite journal | vauthors = Bose A, Gardel EJ, Vidoudez C, Parra EA, Girguis PR | title = Electron uptake by iron-oxidizing phototrophic bacteria | journal = Nature Communications | volume = 5 | pages = 3391 | date = February 2014 | pmid = 24569675 | doi = 10.1038/ncomms4391 | doi-access = free | bibcode = 2014NatCo...5.3391B }}</ref> TIE-1 curiously takes in electrons from materials rich in iron, sulfur, and other minerals found in the sediment beneath the surface. In an extraordinary strategy, as the microbes pull electrons away from iron, iron oxide crystallizes in the soil, eventually becomes conductive, and facilitates TIE-1 in oxidizing other minerals.


TIE-1 then converts these electrons into energy using carbon dioxide as an electron receptor. A gene that produces ruBisCo helps this strain of ''R. palustris'' to achieve energy generation through electrons. TIE-1 uses ruBisCo to convert carbon dioxide into nutrition for itself. This metabolism has phototrophic aspects, since the gene and the ability to uptake electrons are stimulated by sunlight. Therefore, ''R. palustris'' TIE-1 charges itself using minerals located deep in the soil, while using light by remaining on the surface itself. The ability of TIE-1 to use electricity can be used to manufacture batteries, but its efficiency as a fuel source remains questionable, but it has possible applications in the pharmaceutical industry.
| title=Electron uptake by iron-oxidizing phototrophic bacteria
| journal=Nature Communications
| volume=5
| year=2014
| pages=3391
| doi=10.1038/ncomms4391
| bibcode=2014NatCo...5E3391B
| last1=Bose
| first1=A.
| last2=Gardel
| first2=E.J.
| last3=Vidoudez
| first3=C.
| last4=Parra
| first4=E.A.
| last5=Girguis
| first5=P.R.
| pmid=24569675
}}</ref> TIE-1 curiously takes in electrons from materials rich in iron, sulfur and other minerals found in the sediment beneath the surface. In an extraordinary strategy, as the microbes pull electrons away from iron, iron oxide crystallizes in the soil, eventually becomes conductive, and facilitates TIE-1 in oxidizing other minerals.


== References ==
TIE-1 then converts these electrons into energy using carbon dioxide as an electron receptor. A gene that produces ruBisCo helps this strain of ''R. palustris'' to achieve energy generation through electrons. TIE-1 uses ruBisCo to convert carbon dioxide into nutrition for itself. This metabolism has phototrophic aspects, since the gene and the ability to uptake electrons are stimulated by sunlight. Therefore, ''R. palustris'' TIE-1 charges itself using minerals located deep in the soil, while utilizing light by remaining on the surface itself. The ability of TIE-1 to eat electricity can be used to manufacture batteries, but its efficiency as a fuel source remains questionable. However, it has possible applications in the pharmaceutical industry.
{{reflist}}


== External links ==
==References==
*[http://microbewiki.kenyon.edu/index.php/Rhodopseudomonas MicrobeWiki | Rhodopseudomonas]
<references/>
*[https://www.sciencedaily.com/releases/2014/03/140310144000.htm ScienceDaily | "Researchers describe microbe that 'eats' electricity"]


{{Taxonbar|from=Q7321215}}
==External links==
*[http://microbewiki.kenyon.edu/index.php/Rhodopseudomonas MicrobeWiki | Rhodopseudomonas]
*[http://www.sciencedaily.com/releases/2014/03/140310144000.htm ScienceDaily | "Researchers describe microbe that 'eats' electricity"]


[[Category:Rhizobiales]]
[[Category:Nitrobacteraceae]]
[[Category:Bacteria described in 1907]]
[[Category:Bacteria described in 1907]]

Latest revision as of 06:55, 1 April 2024

Rhodopseudomonas palustris
Scientific classification
Domain:
Phylum:
Class:
Order:
Family:
Genus:
Species:
R. palustris
Binomial name
Rhodopseudomonas palustris
(Molisch 1907) van Niel 1944
Synonyms[1]
  • Rhodopseudomonas rutila Akiba et al. 1983

Rhodopseudomonas palustris is a rod-shaped, Gram-negative purple nonsulfur bacterium, notable for its ability to switch between four different modes of metabolism.[2]

R. palustris is found extensively in nature, and has been isolated from swine waste lagoons, earthworm droppings, marine coastal sediments, and pond water. Although purple nonsulfur bacteria are normally photoheterotrophic, R. palustris can flexibly switch among any of the four modes of metabolism that support life: photoautotrophic, photoheterotrophic, chemoautotrophic, or chemoheterotrophic.[2]

Etymology[edit]

R. palustris is usually found as a wad of slimy masses, and cultures appear from pale brown to peach-colored. Etymologically, rhodum is a Greek noun meaning rose, pseudes is the Greek adjective for false, and monas refers to a unit in Greek. Therefore, Rhodopseudomonas, which implies a unit of false rose, describes the appearance of the bacteria. Palustris is Latin for marshy, and indicates the common habitat of the bacterium.[3]

Modes of metabolism[edit]

R. palustris can grow with or without oxygen, or it can use light or inorganic or organic compounds for energy. It can also acquire carbon from either carbon dioxide fixation or green plant-derived compounds. Finally, R. palustris is also capable of fixing nitrogen for growth. This metabolic versatility has raised interest in the research community, and it makes this bacterium suitable for potential use in biotechnological applications.

Efforts are currently being made to understand how this organism adjusts its metabolism in response to environmental changes. The complete genome of the strain Rhodopseudomonas palustris CGA009 was sequenced in 2004 (see list of sequenced bacterial genomes) to get more information about how the bacterium senses environmental changes and regulates its metabolic pathways. R. palustris can deftly acquire and process various components from its environment, as necessitated by fluctuations in the levels of carbon, nitrogen, oxygen, and light.

R. palustris has genes that encode for proteins that make up light-harvesting complexes (LHCs) and photosynthetic reaction centers. LHCs and photosynthetic reaction centers are typically found in photosynthetic organisms such as green plants. Moreover, R. palustris can modulate photosynthesis according to the amount of light available, like other purple bacteria. For instance, in low-light circumstances, it responds by increasing the level of these LHCs that allow light absorption. The wavelengths of the light absorbed by R. palustris differ from those absorbed by other phototrophs.

R. palustris also has genes that encode for the protein ruBisCO, an enzyme necessary for carbon dioxide fixation in plants and other photosynthetic organisms. The genome of CGA009 also reveals the existence of proteins involved in nitrogen fixation (see diazotroph).

In addition, this bacterium can combine oxygen-sensitive and oxygen-requiring enzyme reaction processes for metabolism, thus it can thrive under varying and even very little levels of oxygen.

Commercial applications[edit]

BioFossil Fuel Industry

R. palustris, during its photoautotrophic mode of metabolism possibly uses Vanabin to cleave the core out of Chlorin based compounds such as the Magnesium in Chlorophyll and replaces it with its Vanadium center in order to attach and harvest energy via Light Harvesting Complexes making R. Palustris a potential ingredient in the future of the fuel industry.

Biodegradation[edit]

The genome of R. palustris consists of a variety of genes that are responsible for biodegradation. It can metabolize lignin and acids found in degrading plant and animal waste by metabolizing carbon dioxide.[4] In addition, it can degrade aromatic compounds found in industrial waste.[5] This bacterium is an efficient biodegradation catalyst in both aerobic and anaerobic environments. [citation needed]

Hydrogen production[edit]

Purple phototrophic bacteria have drawn interest for their biotechnological applications. These bacteria can be used for bioplastic synthesis and hydrogen production. R. palustris has the unique characteristic of encoding for a vanadium-containing nitrogenase. It produces, as a byproduct of nitrogen fixation, three times more hydrogen than do molybdenum-containing nitrogenases of other bacteria.[2] The potential to manipulate R. palustris to be used as a reliable hydrogen production source or for biodegradation still lacks detailed knowledge of its metabolic pathways and regulation mechanisms.

Electricity generation[edit]

R. palustris DX-1[edit]

A strain of R. palustris (DX-1) is one of the few microorganisms and the first Alphaproteobacteria found to generate electricity at high power densities in low-internal resistance microbial fuel cells (MFCs).[6] DX-1 produces electric current in MFCs in the absence of a catalyst, without light or hydrogen production. This strain is exoelectrogenic, meaning that it can transfer electrons outside the cell. Other microorganisms isolated from MFCs cannot produce power densities higher than mixed cultures of microbes can under the same fuel-cell conditions, but R. palustris DX-1 can produce significantly higher power densities.

This Rhodopseudomonas species is widely found in wastewaters, and DX-1 generates electricity using compounds that Rhodopseudomonas is known to degrade. Therefore, this technology can be harnessed to produce bioelectricity from biomass and for wastewater treatment. However, the energy generated through this process is currently not sufficient for large-scale wastewater treatment.[7]

Rhodopseudomonas palustris TIE-1[edit]

A 2014 study explained the cellular processes that allow the strain R. palustris TIE-1 to obtain energy through extracellular electron transfer.[8] TIE-1 curiously takes in electrons from materials rich in iron, sulfur, and other minerals found in the sediment beneath the surface. In an extraordinary strategy, as the microbes pull electrons away from iron, iron oxide crystallizes in the soil, eventually becomes conductive, and facilitates TIE-1 in oxidizing other minerals.

TIE-1 then converts these electrons into energy using carbon dioxide as an electron receptor. A gene that produces ruBisCo helps this strain of R. palustris to achieve energy generation through electrons. TIE-1 uses ruBisCo to convert carbon dioxide into nutrition for itself. This metabolism has phototrophic aspects, since the gene and the ability to uptake electrons are stimulated by sunlight. Therefore, R. palustris TIE-1 charges itself using minerals located deep in the soil, while using light by remaining on the surface itself. The ability of TIE-1 to use electricity can be used to manufacture batteries, but its efficiency as a fuel source remains questionable, but it has possible applications in the pharmaceutical industry.

References[edit]

  1. ^ Hiraishi A, Santos TS, Sugiyama J, Komagata K (1992). "Rhodopseudomonas rutila is a Later Subjective Synonym of Rhodopseudomonas palustris". International Journal of Systematic Bacteriology. 42: 186–188. doi:10.1099/00207713-42-1-186.
  2. ^ a b c Larimer FW, Chain P, Hauser L, Lamerdin J, Malfatti S, Do L, et al. (January 2004). "Complete genome sequence of the metabolically versatile photosynthetic bacterium Rhodopseudomonas palustris". Nature Biotechnology. 22 (1): 55–61. doi:10.1038/nbt923. PMID 14704707.
  3. ^ Smith AW (1997). A gardener's handbook of plant names: their meanings and origins (Dover ed.). Mineola, NY: Dover Publications. p. 258. ISBN 978-0-486-29715-6.
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