View source for Biology:Microbial consortium

A '''microbial consortium''' or '''microbial community''', is two or more bacterial or microbial groups living [[Earth:Symbiosis|symbiotically]].<ref name="Brock">{{cite book |last1=Madigan |first1=M |last2=Bender |first2=K |last3=Buckley |first3=D |last4=Sattley |first4=W |last5=Stahl |first5=D |title=Brock biology of microorganisms |date=2019 |publisher=Pearson |location=New York, NY |isbn=9781292235103 |page=173 |edition=Fifteenth, Global}}</ref><ref name='small-things-considered'>{{cite web | url = http://schaechter.asmblog.org/schaechter/2009/04/happy-together-life-of-the-bacterial-consortium-chlorochromatium-aggregatum.html | title = Happy Together… Life of the Bacterial Consortium Chlorochromatium aggregatum | access-date = 2012-01-11 | last = Mark | first = Martin | date = 2009-04-27 | work = Small Things Considered - The Microbe Blog | publisher = American Society for Microbiology | archive-url = https://web.archive.org/web/20090501115354/http://schaechter.asmblog.org/schaechter/2009/04/happy-together-life-of-the-bacterial-consortium-chlorochromatium-aggregatum.html | archive-date = 2009-05-01 | quote = Consortia are assemblages of different species of microbes in physical (and sometimes intricate biochemical) contact with one another, and are implicated in biological processes ranging from sewage treatment to marine nitrogen cycling to metabolic processes within the rumen.}}</ref> Consortiums can be [[Biology:Endosymbiont|endosymbiotic]] or [[Biology:Ectosymbiosis|ectosymbiotic]], or occasionally may be both. The protist ''[[Biology:Mixotricha paradoxa|Mixotricha paradoxa]]'', itself an endosymbiont of the ''[[Biology:Mastotermes darwiniensis|Mastotermes darwiniensis]]'' termite, is always found as a consortium of at least one endosymbiotic [[Biology:Coccus|coccus]], multiple ectosymbiotic species of [[Biology:Flagellate|flagellate]] or ciliate bacteria, and at least one species of helical ''[[Biology:Treponema|Treponema]]'' bacteria that forms the basis of ''Mixotricha'' protists' locomotion.<ref>{{cite book |last1=Thompson |first1=William Irwin |title=Gaia 2 : emergence : the new science of becoming |date=1991 |publisher=Lindisfarne Press |location=Hudson, NY |isbn=9780940262409 |pages=51–58 }}</ref>
The concept of a consortium was first introduced by [[Biography:Johannes Reinke|Johannes Reinke]] in 1872,<ref>Reinke, Johannes 1872. Ueber die anatomischen Verhältnisse einiger Arten von ''Gunnera'' L. ''Nachrichten von der Königl. Gesellschaft der Wissenschaften und der Georg-Augusts-Universität zu Göttingen'' 9: 100–108.</ref><ref>[[Biography:Kalevi Kull|Kull, Kalevi]] 2010. [https://www.academia.edu/233478/Ecosystems_are_made_of_semiosic_bonds_Consortia_umwelten_biophony_and_ecological_codes Ecosystems are made of semiosic bonds: Consortia, umwelten, biophony and ecological codes.] ''Biosemiotics'' 3(3): 347–357.</ref> and in 1877 the term [[Earth:Symbiosis|symbiosis]] was introduced and later expanded on. Evidence for symbiosis between microbes strongly suggests it to have been a necessary precursor of the evolution of land plants and for their transition from algal communities in the sea to land.<ref>{{Cite journal|last1=Delaux|first1=Pierre-Marc|last2=Radhakrishnan|first2=Guru V.|last3=Jayaraman|first3=Dhileepkumar|last4=Cheema|first4=Jitender|last5=Malbreil|first5=Mathilde|last6=Volkening|first6=Jeremy D.|last7=Sekimoto|first7=Hiroyuki|last8=Nishiyama|first8=Tomoaki|last9=Melkonian|first9=Michael|date=2015-10-27|title=Algal ancestor of land plants was preadapted for symbiosis |journal=Proceedings of the National Academy of Sciences of the United States of America|volume=112|issue=43|pages=13390–13395|doi=10.1073/pnas.1515426112 |pmc=4629359|pmid=26438870|bibcode=2015PNAS..11213390D |doi-access=free }}</ref>

==Overview==
[[File:Microbial consortia naturally formed on the roots of Arabidopsis thaliana.webp|thumb|upright=1.7| {{center|'''Microbial consortia naturally formed<br />on the roots of ''Arabidopsis thaliana'''''}} Scanning electron microscopy pictures of root surfaces from natural A. thaliana populations showing the complex microbial networks formed on roots.<br />a) Overview of an [[Biology:Arabidopsis thaliana|''A. thaliana'']] root (primary root) with numerous root hairs. b) Biofilm-forming bacteria. c) Fungal or oomycete hyphae surrounding the root surface. d) Primary root densely covered by spores and protists. e, f) Protists, most likely belonging to the Bacillariophyceae class. g) Bacteria and bacterial filaments. h, i) Different bacterial individuals showing great varieties of shapes and morphological features.<ref>Hassani, M.A., Durán, P. and Hacquard, S. (2018) "Microbial interactions within the plant holobiont". ''Microbiome'', '''6'''(1): 58. {{doi|10.1186/s40168-018-0445-0}}. 50px Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>]]

Microbes hold promising application potential to raise the efficiency of bioprocesses when dealing with substances that are resistant to decomposition.<ref>{{cite journal |doi = 10.1016/j.biotechadv.2011.07.009|title = Consortia of cyanobacteria/Microalgae and bacteria: Biotechnological potential|year = 2011|last1 = Subashchandrabose|first1 = Suresh R.|last2 = Ramakrishnan|first2 = Balasubramanian|last3 = Megharaj|first3 = Mallavarapu|last4 = Venkateswarlu|first4 = Kadiyala|last5 = Naidu|first5 = Ravi|journal = Biotechnology Advances|volume = 29|issue = 6|pages = 896–907|pmid = 21801829}}</ref><ref>{{cite journal |doi = 10.1016/j.copbio.2012.02.001|title = Towards synthetic microbial consortia for bioprocessing|year = 2012|last1 = Shong|first1 = Jasmine|last2 = Jimenez Diaz|first2 = Manuel Rafael|last3 = Collins|first3 = Cynthia H.|journal = Current Opinion in Biotechnology|volume = 23|issue = 5|pages = 798–802|pmid = 22387100}}</ref> A large number of microorganisms have been isolated based on their ability to degrade recalcitrant materials such as lignocellulose and polyurethanes.<ref>{{cite journal |doi = 10.1016/j.cbpa.2013.11.015|title = Exploring bacterial lignin degradation|year = 2014|last1 = Brown|first1 = Margaret E.|last2 = Chang|first2 = Michelle CY|journal = Current Opinion in Chemical Biology|volume = 19|pages = 1–7|pmid = 24780273}}</ref><ref>{{cite journal |doi = 10.1016/j.biotechadv.2013.08.011|title = New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process|year = 2013|last1 = Cregut|first1 = Mickael|last2 = Bedas|first2 = M.|last3 = Durand|first3 = M.-J.|last4 = Thouand|first4 = G.|journal = Biotechnology Advances|volume = 31|issue = 8|pages = 1634–1647|pmid = 23978675}}</ref> In many cases of degradation efficiency, microbial consortia have been found superior when compared to single strains.<ref>{{cite journal |doi = 10.1007/s00253-012-4234-6|title = Interspecific interactions in mixed microbial cultures in a biodegradation perspective|year = 2012|last1 = Mikesková|first1 = H.|last2 = Novotný|first2 = Č.|last3 = Svobodová|first3 = K.|journal = Applied Microbiology and Biotechnology|volume = 95|issue = 4|pages = 861–870|pmid = 22733114|s2cid = 7420481}}</ref> For example, novel thermophilic consortia of Brevibacillus spp. and Aneurinibacillus sp. have been isolated from the environment to enhance polymer degradation.<ref>{{cite journal |doi = 10.1016/j.polymdegradstab.2018.01.018|title = Enhanced polymer degradation of polyethylene and polypropylene by novel thermophilic consortia of Brevibacillus SPS. And Aneurinibacillus sp. Screened from waste management landfills and sewage treatment plants|year = 2018|last1 = Skariyachan|first1 = Sinosh|last2 = Patil|first2 = Amulya A.|last3 = Shankar|first3 = Apoorva|last4 = Manjunath|first4 = Meghna|last5 = Bachappanavar|first5 = Nikhil|last6 = Kiran|first6 = S.|journal = Polymer Degradation and Stability|volume = 149|pages = 52–68}}</ref>

Two approaches exist to obtain microbial consortia involving either (i) a synthetic assembly from scratch by combining several isolated strains,<ref>{{cite journal |doi = 10.1016/j.polymdegradstab.2018.01.018|title = Enhanced polymer degradation of polyethylene and polypropylene by novel thermophilic consortia of Brevibacillus SPS. And Aneurinibacillus sp. Screened from waste management landfills and sewage treatment plants|year = 2018|last1 = Skariyachan|first1 = Sinosh|last2 = Patil|first2 = Amulya A.|last3 = Shankar|first3 = Apoorva|last4 = Manjunath|first4 = Meghna|last5 = Bachappanavar|first5 = Nikhil|last6 = Kiran|first6 = S.|journal = Polymer Degradation and Stability|volume = 149|pages = 52–68}}</ref> or (ii) obtainment of complex microbial communities from environmental samples.<ref>{{cite journal |doi = 10.1007/s11356-017-8537-0|title = Enhanced biodegradation of low and high-density polyethylene by novel bacterial consortia formulated from plastic-contaminated cow dung under thermophilic conditions|year = 2017|last1 = Skariyachan|first1 = Sinosh|last2 = Setlur|first2 = Anagha Shamsundar|last3 = Naik|first3 = Sujay Yashwant|last4 = Naik|first4 = Ashwini Amaresh|last5 = Usharani|first5 = Makam|last6 = Vasist|first6 = Kiran S.|journal = Environmental Science and Pollution Research|volume = 24|issue = 9|pages = 8443–8457|pmid = 28188552|s2cid = 9776975}}</ref> For the later, enrichment process is often used to get the desired microbial consortia.<ref>{{cite journal |doi = 10.1111/1462-2920.13121|title = Cultivating microbial dark matter in benzene-degrading methanogenic consortia|year = 2016|last1 = Luo|first1 = Fei|last2 = Devine|first2 = Cheryl E.|last3 = Edwards|first3 = Elizabeth A.|journal = Environmental Microbiology|volume = 18|issue = 9|pages = 2923–2936|pmid = 26549712}}</ref><ref>{{cite journal |doi = 10.1016/j.watres.2018.02.029|title = Combined polyhydroxyalkanoates (PHA) and 1,3-propanediol production from crude glycerol: Selective conversion of volatile fatty acids into PHA by mixed microbial consortia|year = 2018|last1 = Burniol-Figols|first1 = Anna|last2 = Varrone|first2 = Cristiano|last3 = Le|first3 = Simone Balzer|last4 = Daugaard|first4 = Anders Egede|last5 = Skiadas|first5 = Ioannis V.|last6 = Gavala|first6 = Hariklia N.|journal = Water Research|volume = 136|pages = 180–191|pmid = 29505919}}</ref><ref name=Kang2018>{{cite journal |doi = 10.1016/j.biortech.2018.09.006|title = Enrichment and characterization of an environmental microbial consortium displaying efficient keratinolytic activity|year = 2018|last1 = Kang|first1 = Dingrong|last2 = Herschend|first2 = Jakob|last3 = Al-Soud|first3 = Waleed Abu|last4 = Mortensen|first4 = Martin Steen|last5 = Gonzalo|first5 = Milena|last6 = Jacquiod|first6 = Samuel|last7 = Sørensen|first7 = Søren J.|journal = Bioresource Technology|volume = 270|pages = 303–310|pmid = 30236907}}</ref> For instance, a termite gut-derived consortium showing a high xylanase activity was enriched on raw wheat straw as the sole carbon source, which was able to transform lignocellulose into carboxylates under anaerobic conditions.<ref>{{cite journal |doi = 10.1186/s13068-018-1282-x|title = Anaerobic lignocellulolytic microbial consortium derived from termite gut: Enrichment, lignocellulose degradation and community dynamics|year = 2018|last1 = Lazuka|first1 = Adèle|last2 = Auer|first2 = Lucas|last3 = o'Donohue|first3 = Michael|last4 = Hernandez-Raquet|first4 = Guillermina|journal = Biotechnology for Biofuels|volume = 11|page = 284|pmid = 30356893|pmc = 6191919 | doi-access=free }}</ref>

Relatively high diversity levels are still observed despite the use of enrichment steps when working from environmental samples,<ref name=Kang2018 /> likely due to the high functional redundancy observed in environmental microbial communities, being a key asset of their functional stability.<ref>{{cite journal |doi = 10.3389/fmicb.2012.00417|title = Fundamentals of Microbial Community Resistance and Resilience|year = 2012|last1 = Shade|first1 = Ashley|last2 = Peter|first2 = Hannes|last3 = Allison|first3 = Steven D.|last4 = Baho|first4 = Didier L.|last5 = Berga|first5 = Mercè|last6 = Bürgmann|first6 = Helmut|last7 = Huber|first7 = David H.|last8 = Langenheder|first8 = Silke|last9 = Lennon|first9 = Jay T.|last10 = Martiny|first10 = Jennifer B. H.|last11 = Matulich|first11 = Kristin L.|last12 = Schmidt|first12 = Thomas M.|last13 = Handelsman|first13 = Jo|journal = Frontiers in Microbiology|volume = 3|page = 417|pmid = 23267351|pmc = 3525951 | doi-access=free }}</ref><ref>{{cite journal |doi = 10.1038/ismej.2014.91|title = Biodiversity acts as insurance of productivity of bacterial communities under abiotic perturbations|year = 2014|last1 = Awasthi|first1 = Ashutosh|last2 = Singh|first2 = Mangal|last3 = Soni|first3 = Sumit K.|last4 = Singh|first4 = Rakshapal|last5 = Kalra|first5 = Alok|journal = The ISME Journal|volume = 8|issue = 12|pages = 2445–2452|pmid = 24926862|pmc = 4260711}}</ref> This intrinsic diversity may stand as a bottleneck in attempts to move forward to practical application due to (i) potential negative correlation with efficiency,<ref>{{cite journal |doi = 10.1016/j.soilbio.2016.03.017|title = Network analysis reveals functional redundancy and keystone taxa amongst bacterial and fungal communities during organic matter decomposition in an arable soil|year = 2016|last1 = Banerjee|first1 = Samiran|last2 = Kirkby|first2 = Clive A.|last3 = Schmutter|first3 = Dione|last4 = Bissett|first4 = Andrew|last5 = Kirkegaard|first5 = John A.|last6 = Richardson|first6 = Alan E.|journal = Soil Biology and Biochemistry|volume = 97|pages = 188–198}}</ref> (ii) real microbial cheaters whose presence has no impacts on degradation, (iii) security threats posed by the presence of known or unknown pathogens, and (iv) risks of losing the properties of interest if supported by rare taxa.<ref name=Kang2020>{{cite journal |doi = 10.3389/fmicb.2019.03010|title = Construction of Simplified Microbial Consortia to Degrade Recalcitrant Materials Based on Enrichment and Dilution-to-Extinction Cultures|year = 2020|last1 = Kang|first1 = Dingrong|last2 = Jacquiod|first2 = Samuel|last3 = Herschend|first3 = Jakob|last4 = Wei|first4 = Shaodong|last5 = Nesme|first5 = Joseph|last6 = Sørensen|first6 = Søren J.|journal = Frontiers in Microbiology|volume = 10|page = 3010|pmid = 31998278|pmc = 6968696 | doi-access=free }} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>

Utilization of microbial consortia with less complexity, but equal efficiency, can lead to more controlled and optimized industrial processes.<ref name="Puentes-Téllez2018">{{cite journal |doi = 10.1007/s00248-017-1141-5|title = Construction of Effective Minimal Active Microbial Consortia for Lignocellulose Degradation|year = 2018|last1 = Puentes-Téllez|first1 = Pilar Eliana|last2 = Falcao Salles|first2 = Joana|journal = Microbial Ecology|volume = 76|issue = 2|pages = 419–429|pmid = 29392382|pmc = 6061470}}</ref> For instance, a large proportion of functional genes were remarkably altered and the efficiency of diesel biodegradation was increased by reducing the biodiversity of a microbial community from diesel-contaminated soils.<ref>{{cite journal |doi = 10.1038/srep23012|title = Metagenomic and functional analyses of the consequences of reduction of bacterial diversity on soil functions and bioremediation in diesel-contaminated microcosms|year = 2016|last1 = Jung|first1 = Jaejoon|last2 = Philippot|first2 = Laurent|last3 = Park|first3 = Woojun|journal = Scientific Reports|volume = 6|page = 23012|pmid = 26972977|pmc = 4789748|bibcode = 2016NatSR...623012J}}</ref> Therefore, it is crucial to find reliable strategies to narrow down the diversity toward optimized microbial consortia gained from environmental samples. A reductive-screening approach was applied to construct effective minimal microbial consortia for lignocellulose degradation based on different metabolic functional groups.<ref name="Puentes-Téllez2018" /> Additionally, artificial selection approaches (dilution, toxicity, and heat) have been also employed to obtain bacterial consortia.<ref>{{cite journal |doi = 10.1016/j.biortech.2013.02.075|title = Unconventional approaches to isolation and enrichment of functional microbial consortium – A review|year = 2013|last1 = Lee|first1 = Duu-Jong|last2 = Show|first2 = Kuan-Yeow|last3 = Wang|first3 = Aijie|journal = Bioresource Technology|volume = 136|pages = 697–706|pmid = 23566469}}</ref> Among them, dilution-to-extinction has already proven its efficiency for obtaining functional microbial consortia from seawater and rumen liquor .<ref>{{cite journal |doi = 10.1016/j.ijhydene.2012.01.137|title = Biohydrogen from lignocellulosic feedstock via one-step process|year = 2012|last1 = Ho|first1 = Kuo-Ling|last2 = Lee|first2 = Duu-Jong|last3 = Su|first3 = Ay|last4 = Chang|first4 = Jo-Shu|journal = International Journal of Hydrogen Energy|volume = 37|issue = 20|pages = 15569–15574}}</ref><ref>{{cite journal |doi = 10.1111/j.1751-7915.2011.00314.x|title = Miniaturized extinction culturing is the preferred strategy for rapid isolation of fast-growing methane-oxidizing bacteria|year = 2012|last1 = Hoefman|first1 = Sven|last2 = Van Der Ha|first2 = David|last3 = De Vos|first3 = Paul|last4 = Boon|first4 = Nico|last5 = Heylen|first5 = Kim|journal = Microbial Biotechnology|volume = 5|issue = 3|pages = 368–378|pmid = 22070783|pmc = 3821679}}</ref><ref>{{cite journal |doi = 10.1038/ismej.2015.68|title = High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures|year = 2015|last1 = Sosa|first1 = Oscar A.|last2 = Gifford|first2 = Scott M.|last3 = Repeta|first3 = Daniel J.|last4 = Delong|first4 = Edward F.|journal = The ISME Journal|volume = 9|issue = 12|pages = 2725–2739|pmid = 25978545|pmc = 4817625}}</ref> Dilution-to-extinction is expected to provide more advantages compared to conventional isolation and assembly as it (i) generates many microbial combinations ready to be screened, (ii) includes strains from the initial microbial pool that might be lost due to cultivation/isolation biases, and (iii) ensures that all microbes are physically present and interacting spontaneously.<ref>{{cite journal |doi = 10.1002/ecy.1518|title = Effects of multiple dimensions of bacterial diversity on functioning, stability and multifunctionality|year = 2016|last1 = Roger|first1 = Fabian|last2 = Bertilsson|first2 = Stefan|last3 = Langenheder|first3 = Silke|last4 = Osman|first4 = Omneya Ahmed|last5 = Gamfeldt|first5 = Lars|journal = Ecology|volume = 97|issue = 10|pages = 2716–2728|pmid = 27859115}}</ref><ref name=Kang2020 />

==Examples==

=== Microbialites ===
[[Earth:Microbialite|Microbialite]]s are lithified microbial mats that grow in benthic freshwater and marine environments. Microbialites are the earliest known fossilised evidence of life, dating back 3.7 billion years.{{cn|date=November 2021}} Today modern microbialites are scarce, and are formed mainly by [[Biology:Pseudomonadota|Pseudomonadota]] (formerly Proteobacteria), [[Biology:Cyanobacteria|cyanobacteria]], sulphate-reducing bacteria, [[Biology:Diatom|diatom]]s, and [[Biology:Microalgae|microalgae]].{{cn|date=November 2021}} These [[Biology:Microorganism|microorganism]]s produce adhesive compounds that [[Earth:Cementation (geology)|cement]] sand and join other rocky materials to form mineral "[[Biology:Microbial mat|microbial mat]]s". The mats build layer by layer, growing gradually over time.{{cn|date=November 2021}}

===Rhizosphere===
[[File:Rhizosphere microbial consortia.webp|thumb|upright=2|right| {{center|'''Rhizosphere microbial consortia'''{{hsp}}<ref name=Santoyo2021 />}}]]

Although various studies have shown that single microorganisms can exert beneficial effects on plants, it is increasingly evident that when a microbial consortium — two or more interacting microorganisms — is involved, additive or synergistic results can be expected. This occurs, in part, due to the fact that multiple species can perform a variety of tasks in an ecosystem like the plant root [[Earth:Rhizosphere|rhizosphere]]. Beneficial mechanisms of plant growth stimulation include enhanced nutrient availability, phytohormone modulation, biocontrol, biotic and [[Earth:Abiotic component|abiotic]] stress tolerance) exerted by different microbial players within the rhizosphere, such as plant-growth-promoting bacteria (PGPB) and fungi such as ''[[Biology:Trichoderma|Trichoderma]]'' and ''Mycorrhizae''.<ref name=Santoyo2021>{{cite journal |doi = 10.3390/agronomy11020219|doi-access = free|title = Plant Growth Stimulation by Microbial Consortia|year = 2021|last1 = Santoyo|first1 = Gustavo|last2 = Guzmán-Guzmán|first2 = Paulina|last3 = Parra-Cota|first3 = Fannie Isela|last4 = Santos-Villalobos|first4 = Sergio de los|last5 = Orozco-Mosqueda|first5 = Ma. del Carmen|last6 = Glick|first6 = Bernard R.|journal = Agronomy|volume = 11|issue = 2|page = 219}} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>

The diagram on the right illustrates that rhizosphere microorganisms like plant-growth-promoting bacteria (PGPB), arbuscular mycorrhizal fungi (AMF), and fungi from the genus Trichoderma spp. can establish beneficial interactions with plants, promoting plant growth and development, increasing the plant defense system against pathogens, promoting nutrient uptake, and enhancing tolerance to different environmental stresses. Rhizosphere microorganisms can influence one another, and the resulting consortia of PGPB + PGPB (e.g., a nitrogen-fixing bacterium such as ''[[Biology:Rhizobium|Rhizobium]]'' spp. and ''[[Biology:Pseudomonas fluorescens|Pseudomonas fluorescens]]''), AMF + PGPB, and Trichoderma + PGPB may have synergetic effects on plant growth and fitness, providing the plant with enhanced benefits to overcome biotic and abiotic stress. Dashed arrows indicate beneficial interactions between AMF and Trichoderma.<ref name=Santoyo2021 />

===Keratin degradation===
[[File:Selection of microbial consortia for keratin degradation.jpg|thumb|upright=1.7| Workflow of enrichment and dilution-to-extinction cultures to select simplified microbial consortia (SMC) for keratin degradation.<ref name=Kang2020 />]]

The capacity of microbes to degrade recalcitrant materials has been extensively explored for environmental remediation and industrial production. Significant achievements have been made with single strains, but focus is now going toward the use of microbial consortia owing to their functional stability and efficiency. However, assembly of simplified microbial consortia (SMC) from complex environmental communities is still far from trivial due to large diversity and the effect of biotic interactions.<ref name=Kang2020 />

[[Biology:Keratin|Keratin]]s are recalcitrant fibrous materials with cross-linked components, representing the most abundant proteins in epithelial cells.<ref>{{cite journal |doi = 10.1016/s0955-0674(01)00301-5|title = 'Hard' and 'soft' principles defining the structure, function and regulation of keratin intermediate filaments|year = 2002|last1 = Coulombe|first1 = Pierre A.|last2 = Omary|first2 = M.Bishr|journal = Current Opinion in Cell Biology|volume = 14|issue = 1|pages = 110–122|pmid = 11792552}}</ref> They are estimated to have considerable economic value after biodegradation.<ref>{{cite journal |doi = 10.1016/j.wasman.2011.03.024|title = Biodegradation of keratin waste: Theory and practical aspects|year = 2011|last1 = Korniłłowicz-Kowalska|first1 = Teresa|last2 = Bohacz|first2 = Justyna|journal = Waste Management|volume = 31|issue = 8|pages = 1689–1701|pmid = 21550224}}</ref> An efficient keratinolytic microbial consortium (KMCG6) was previously enriched from an environmental sample through cultivation in keratin medium.<ref name=Kang2018 /> Despite reducing the microbial diversity during the enrichment process, KMCG6 still included several [[Operational taxonomic unit|OTUs]] scattered amongst seven bacterial genera.<ref name=Kang2020 />

In 2020 Kang et al., using a strategy based on [[Biology:Enrichment culture|enrichment]] and dilution-to-extinction cultures, extracted from this original consortium (KMCG6) a simplified microbial consortia (SMC) with fewer species but similar keratinolytic activity.<ref name=Kang2020 /> Serial dilutions were performed on a keratinolytic microbial consortium pre-enriched from a soil sample. An appropriate dilution regime (10<sup>9</sup>) was selected to construct a SMC library from the enriched microbial consortium. Further [[Biology:DNA sequencing|sequencing analysis]] and keratinolytic activity [[Biology:Assay|assay]]s demonstrated that obtained SMC displayed actual reduced microbial diversity, together with various taxonomic composition, and biodegradation capabilities. More importantly, several SMC possessed equivalent levels of keratinolytic efficiency compared to the initial consortium, showing that simplification can be achieved without loss of function and efficiency.<ref name=Kang2020 />

As shown in the diagram on the right, the workflow for this study included four steps: (1) Enrichment for the desired traits e.g., keratinolytic activity by selection in keratin medium, where keratin is the sole carbon source. This process was evaluated by functional assessments (cell density, enzymes activity, and ratio of the residual substrate) and compositional analysis. (2) Serial dilutions were conducted to the enriched effective microbial consortia. Six dilutions were prepared, from dilution 10<sup>2</sup> to 10<sup>10</sup> with 24 replicates. The dissimilarity between dilutions was evaluated by Euclidean distance calculation based on functional assessment criteria. (3) Library construction was done from the dilution offering the optimal dissimilarity among replicates. Dilution 10<sup>9</sup> was selected to construct the SMC library in this case. (4) Selection of the most promising SMC is based on functional and compositional characterization.<ref name=Kang2020 />

===Human health===
Consortia are commonly found in humans, with the predominant examples being the [[Biology:Skin flora|skin consortium]] and the [[Biology:Gut flora|intestinal consortium]] which provide protection and aid in human nutrition. Additionally, bacteria have been identified as existing within the brain (previously believed to be sterile), with metagenomic evidence suggesting the species found may be enteric in origin.<ref>{{cite news |last1=Pennisi |first1=Elizabeth |title=Meet the 'psychobiome': the gut bacteria that may alter how you think, feel, and act |url=https://www.science.org/content/article/meet-psychobiome-gut-bacteria-may-alter-how-you-think-feel-and-act |access-date=12 December 2020 |publisher=Science Magazine |date=7 May 2020}}</ref><ref>{{cite news |last1=Rettner |first1=Rachel |title=Bacteria May Live (Harmlessly) in Your Brain |url=https://www.livescience.com/64098-bacteria-brain-microbiome.html |access-date=12 December 2020 |work=livescience.com |publisher=Live Science |date=15 November 2018 |language=en}}</ref> As the species found appear to be well-established, have no discernible impact on human health, and are species known to form consortia when found in the gut, it is highly likely they have also formed a symbiotic consortium within the brain.<ref>{{cite journal |last1=Roberts |first1=R. C. |last2=Farmer |first2=C. B. |last3=Walker |first3=C. K. |title=The human brain microbiome; there are bacteria in our brains! |journal=Psychiatry and Behavioral Neurobio., Univ. Of Alabama, Birmingham, Birmingham, AL. |date=6 November 2018 |volume=2018 Neuroscience Meeting Planner. |issue=Program No. 594.08 |url=https://www.abstractsonline.com/pp8/#!/4649/presentation/32057 |access-date=12 December 2020}}</ref>

==Synthetic microbial consortia==
[[File:Escherichia-coli-bacterium(1).tif|thumb|upright=1| Painting of a cross-section through an ''[[Biology:Escherichia coli|Escherichia coli]]'' bacterium, a  chemoheterotrophic bacterium often used in synthetic microbial consortia.]]
{{main|Biology:Synthetic microbial consortia}}

[[Biology:Synthetic microbial consortia|Synthetic microbial consortia]] (commonly called co-cultures) are multi-population systems that can contain a diverse range of microbial species, and are adjustable to serve a variety of industrial and ecological interests.  For [[Biology:Synthetic biology|synthetic biology]], consortia take the ability to engineer novel cell behaviors to a population level. Consortia are more common than not in nature, and generally prove to be more robust than monocultures.<ref name=":0">{{cite journal |last1=Hays |first1=Stephanie G. |last2=Ducat |first2=Daniel C. |title=Engineering cyanobacteria as photosynthetic feedstock factories |journal=Photosynthesis Research |date=14 February 2014 |volume=123 |issue=3 |pages=285–295 |doi=10.1007/s11120-014-9980-0 |pmc=5851442 |pmid=24526260 }}</ref> Just over 7,000 species of bacteria have been cultured and identified to date. Many of the estimated 1.2 million bacteria species that remain have yet to be cultured and identified, in part due to inabilities to be cultured [[Biology:Axenic|axenic]]ally.<ref>{{Cite journal|last=Stewart|first=Eric J.|date=2012-08-15|title=Growing Unculturable Bacteria |journal=Journal of Bacteriology|language=en|volume=194|issue=16|pages=4151–4160|doi=10.1128/JB.00345-12 |pmid=22661685|pmc=3416243}}</ref>  When designing synthetic consortia, or editing naturally occurring consortia, synthetic biologists keep track of pH, temperature, initial metabolic profiles, incubation times, growth rate, and other pertinent variables.<ref name=":0" />

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== See also ==
* [[Earth:Biofilm|Biofilm]]
* [[Philosophy:Microbial intelligence|Microbial intelligence]]
* [[Biology:Microbial loop|Microbial loop]]
* [[Biology:Microbial mat|Microbial mat]]
* [[Biology:Microbial population biology|Microbial population biology]]
* [[Biology:Synthetic microbial consortia|Synthetic microbial consortia]]
* [[Biology:Microbial cooperation|Microbial cooperation]]

==Notes==
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{{microorganisms}}

[[Category:Microorganisms]]

{{Sourceattribution|Microbial consortium}}