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'''''Pediococcus''''' (often referred to by brewers as "Pedio") are Gram-positive lactic acid bacteria (LAB) used in the production of Belgian style beers where additional acidity is desirable. They are native to plant material and fruits <ref name="ucdavis">[http://wineserver.ucdavis.edu/industry/enology/winemicro/winebacteria/pediococcus_damnosus.html Viticulture & Enology. UC Davis website. Pedioccous damnosus. Retreived Retrieved 07/28/2015.]</ref>, and often found in [[Spontaneous_Fermentation|spontaneously fermented ]] beer as the primary source of lactic acid production (with ''P. damnosus'' being the only species identified in lambic[[Lambic]]) <ref>[http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0095384 The Microbial Diversity of Traditional Spontaneously Fermented Lambic Beer. Freek Spitaels, Anneleen D. Wieme, Maarten Janssens, Maarten Aerts, Heide-Marie Daniel, Anita Van Landschoot, Luc De Vuyst, Peter Vandamme. April 18, 2014.]</ref><ref>[[Scientific_Publications#Lambic_and_Spontaneous_Fermentation|Multiple Scientific publications linked on MTF.]]</ref>. It is also seen as a major source of beer contamination in commercial breweries due to its ability to adapt to and survive in beer. The ability to grow in beer is strain dependent rather than species dependent, however , genetic differences indicate that ''P. damnosus'' and ''P. claussenii'' are better adapted to surviving in beer than ''P. pentosaceus'' <ref name="Snauwaert">[http://www.biomedcentral.com/content/pdf/s12864-015-1438-z.pdf Comparative genome analysis of Pediococcus damnosus LMG 28219, a strain well-adapted to the beer environment. Isabel Snauwaert, Pieter Stragier, Luc De Vuyst and Peter Vandamme. 2015.]</ref>. Like many bacteria, Pediococci pediococci have the ability to [https://en.wikipedia.org/wiki/Horizontal_gene_transfer transfer genes horizontally] without reproduction <ref name="Snauwaert"></ref>. They are generally considered to be facultative anaerobes, which means they grow anaerobically but can also grow in the presence of oxygen <ref>[http://textbookofbacteriology.net/lactics.html Lactic Acid Bacteria. Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Pg 1. Retrieved 08/09/2015.]</ref>. Some species/strains (including individual strains of ''P. damnosus'') can have their growth and acid production inhibited by oxygen <ref name="NAKAGAWA">[https://www.jstage.jst.go.jp/article/jgam1955/5/3/5_3_95/_article TAXONOMIC STUDIES ON THE GENUS PEDIOCOCCUS. ATSUSHI NAKAGAWA, KAKUO KITAHARA. 1959.]</ref>, while some will have better growth and produce more acid in the presence of oxygen (microaerophilic) <ref>[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC357257/ THE NUTRITION AND PHYSIOLOGY OF THE GENUS PEDIOCOCCUS. Erling M. Jensen and Harry W. Seeley. 1954.]</ref><ref>[http://www.microbialcellfactories.com/content/8/1/3#B5 Pediocins: The bacteriocins of Pediococcipediococci. Sources, production, properties and applications. Maria Papagianni and Sofia Anastasiadou. 2009.]</ref>. Strains found in beer are hop tolerant <ref>[http://www.biomedcentral.com/1471-2164/16/267 Comparative genome analysis of Pediococcus damnosus LMG 28219, a strain well-adapted to the beer environment. Isabel Snauwaert, Pieter Stragier, Luc De Vuyst and Peter Vandamme. April 2015.]</ref>. Due to their continued metabolism of longer chain polysaccharides, acid production will increase with storage time. ''Pediococcus'' can form a [[pellicle]].

''Pediococcus'' may also cause “ropiness” (also called a "sick beer") due to the production of exopolysaccharideswhen exposed to a fresh sugar source. "Ropy" or "sick" beer is more viscous and, in extreme circumstances, can form strands. Sickness effects mostly the mouthfeel and appearance of the beer, and may have no influence on the flavor. It is considered a temporary flaw in sour beer. Some brewers, including Vinnie Cilurzo from Russian River Brewing and some Belgian lambic producers, claim that after the ropiness goes away (generally in 3-6 months <ref name="ropy_time"></ref>) it produces a deeper acidity and mouthfeel, and is viewed as a positive process in the production of sour beer <ref>[http://www.xxlbrewing.com/hb/sour_beer/img_09.html Cilurzo, Vinnie. AHA Sour Beer presentation. 2007.]</ref>. For other brewers, ropy beer is seen as a nuisance due to the beer needing to be aged for a longer period of time, especially when it occurs shortly after bottling. ''Pediococcus'' species can also produce diacetyl with extended storage time<ref name="Garcia-Garcia" />. ''[[Brettanomyces]] '' can break down exopolysaccharides and diacetyl produced by ''Pediococcus'' and the two are often used together.

See ''[[Lactobacillus]]'', ''[[Brettanomyces]]'', ''[[Saccharomyces]]'', and [[Mixed Cultures]], [[Kveik#Commercial_Availability|Kveik]], and [[Nonconventional Yeasts and Bacteria]] charts for other commercially available cultures.  ==Introduction of Characteristics and Taxonomy==''Pediococcus'' can either improve or detract from fermented food products, including beer, wine, and cider. They play an important role in the fermentation of some meats and cheeses. They tend to be the primary souring microorganism in the production of [[Lambic|Belgian lambic]]. Some species have also been isolated from plants, fruit, and fermenting plant material. In wine, ''P. parvulus'' is the most common species found, and in beer ''P. damnosus'' is the most common. ''P. pentosaceus'' tends to be more hop sensitive than ''P. damnosus'' <ref name="Wade_2018">[https://onlinelibrary.wiley.com/doi/full/10.1111/ajgw.12366 Role of Pediococcus in winemaking. M.E. Wade, M.T. Strickland, J.P. Osborn, C.G. Edwards. 2018. DOI: https://doi.org/10.1111/ajgw.12366.]</ref>.  Currently, there are 11 recognized species of ''Pediococcus''. They are ''P. acidilactici'', ''P. argentinicus'', ''P. cellicola'', ''P. claussenii'', ''P. damnosus'', ''P. ethanolidurans'', ''P. inopinatus'', ''P. parvulus'', ''P. pentosaceus'' (subspecies ''pentosaceus'' and ''intermedius''), ''P. siamensis'', and ''P. stilesii''. ''P. cerevisiae'' was reclassified into either ''P. damnosus'' or ''P. pentosaceus''. Other species of ''Pediococcus'' have also been reclassified to other genera in the last couple of decades. ''P. dextrinicus'' is now classified as ''Lactobacillus dextrinicus'', ''P. urinae-equi'' is now classified as ''Aerococcus urinae‐equi'', and ''P. halophilis'' is now classified as ''Tetragenococcus halophilis'' <ref name="Wade_2018" />. Pediococci are described as coccoidal (spherical) or ovoid (egg-shaped) in shape. They are Gram-positive, non-motile (not capable of moving on their own), and non-spore forming. They are obligate homofermentive and typically do not produce CO₂, ethanol, or acetic acid, although there are a few exceptions to this in the literature. They do not produce [https://en.wikipedia.org/wiki/Catalase catalase] (except for some ''P. pentocaseus'' strains which were reported to have pseudo-catalase activity by Simpson and Taguchi 1995) or [https://en.wikipedia.org/wiki/Oxidase oxidase] enzymes. Because of the way that ''Pedioccous'' cells divide, they often appear stuck together in pairs or clumps. They are the only lactic acid bacteria found in wine and beer to do this, so they are easily identifiable at the genus level under a microscope based on their tendency to clump together. When grown on agar that is supplemented with 100 mg/L of pimaricin, the colonies are white-grey with a diameter of about 1 mm. Ropy strains have a high elasticity, and when touched with a needle, long threads can be drawn and sometimes the colonies completely stick to the needle. See [https://onlinelibrary.wiley.com/doi/full/10.1111/ajgw.12366 table 2 from Wade et al. (2018)] for more species identification indicators and what carbohydrates different species can ferment <ref name="Wade_2018" /><ref name="Oevelen_1979">[https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-37-0034 D. Van Oevelen & H. Verachtert (1979) Slime Production by Brewery Strains of Pediococcus Cerevisiae, Journal of the American Society of Brewing Chemists, 37:1, 34-37, DOI: 10.1094/ASBCJ-37-0034.]</ref>. See also:* [https://wol-prod-cdn.literatumonline.com/cms/attachment/fcb6edb6-00be-4757-822c-be0a341a4191/ajgw12366-fig-0001-m.jpg Microscopy image of ''Pediococcus''.]

| [[White LabsBootleg Biology]]/[[Spot Yeast]] || WLP661 Sour Weapon P (''Pediococcus pentosaceus'' Blend) || damnosus ''P. pentosaceus'' blend || High diacetyl (Perfect for acidifying unhopped wort quickly for kettle or “quick” sours. At 98F, it’s capable of achieving a pH of 3.3 within 18 hours. At 84F, it can reach apH of 3.k5 within 24 hours.With more time, aterminal pH of 3. butter) producer 1 may be reached. ''P. pentosaceus'' can also be used for long-term sours. It is capable of growing and slow growingproducing lactic acid in worts with IBUs as high as 30, though it is recommended for unhopped worts as IBUs over 10 may prevent significant quick souring. Fermentation tempAt ~30 IBU, souring occurs in 2-3 months <ref>[https: 70//www.facebook.com/groups/MilkTheFunk/permalink/1302981419730069/?comment_id=1870460696315469&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Justin Amaral and Per Karlsson on Bootleg biology Sour Weapon hop tolerance. milk The Funk Facebook group. 11/2/2017.]</ref>. This culture may produce antimicrobials called bacteriocins or pediocins. These can inhibit and kill similar species of bacteria like Lactobacillus and other Pediococcus species in mixed-85°F culture fermentations. Read Bootleg Biology's [https://www.facebook.com/BootlegBiology/photos/a.148869931970401.1073741829.124634287727299/465185997005458/?type=1&theater Facebook post] regarding bacteriocins for more info. No signs of ropiness (21exopolysaccharides) have occurred in testing <ref>[http://bootlegbiology.com/product/sour-weapon-pediococcus-pentosaceus-29blend/ Bootleg Biology website.4° C) Retrieved 05/06/2016.]</ref>. Attenuation: 65% It is still unknown how hops will affect souring in a long term scenario. Cell countBootleg Biology is still researching long term effects and awaiting peoples feedback as of 5/23/2016.|- | [[East Coast Yeast]] || ECY33 || ''P. parvulus'' || Isolated from lambic which was refermented with grapes, this strain of ''Pediococcus'' produces lactic acid, diacetyl, and may cause ropiness in beer. Always add ''Brettanomyces'' where ''Pediococcus'' is used <ref name="ecy_website">[http: 50//www.eastcoastyeast.com/wild-80 million cellsstuff.html "Wild Yeast / Brettanomyces /mL Lactic Bacteria". East Coast Yeast website. Retrieved 04/27/2018.]</ref>. |-| [[Escarpment Laboratories]] || Pediococcus Blend || Two ''Pediococcus'' strains (''P. damnosus'' and ''P. pentosaceus'') || This blend of 2 hop-resistant Pediococcus strains (P. damnosus and P. pentosaceus) is intended for use in long-term souring. Neither strain has been observed to produce exopolysaccharides (EPS). We recommend 15 IBU or less in the first generation.|-| [[Inland Island Brewing & Consulting|Inland Island Yeast Laboratories]] || INISBC-998 || ''P. damnosus'' || Gram positive cocci that produces lactic acid. Also produces diacetyl and several proteins that may cause a "rope" to form in the beer. Rope will disappear with time. Oxygen and hop sensitive. 75-90°F Temperature Range. '''No longer available.'''|-| [[Mainiacal Yeast]] (CLOSED) || MYPP1 || ''P. pentocaceus'' || Isolated from a growing marijuana plant. No production of diacetyl or EPS, with a clean acidity. Ferment at 70-100°F <ref name="WL_cellcountsAmaral_Mainiacal">Private correspondence with White Labs Customer Service and Justin Amaral by Dan Pixley. 1001/2924/20152018.</ref>. Homebrew vials contain 35 mL Commercial pitches only.|-| [[Mainiacal Yeast]] (CLOSED) || MYPD1 || ''P. damnosus'' || Isolated from a bottle of slurrybelgian lambic. Produces diacetyl and EPS, and ~1so use in conjunction with ''Brettanomyces''.75 Ferment at 70-2.8 billion cells per vial 90°F <ref name="priess_pitchesAmaral_Mainiacal"/>. Commercial pitches only.|-| [[Omega Yeast Labs]] || OYL-606 || ''P. damnosus'' || This modestly hop tolerant Pedio strain produces a clean lactic tang over time. The strain can produce diacetyl so it is often paired with one or more Brett strains (to consume the diacetyl). While more hop tolerant than the Lacto Blend (OYL-605), IBUs over 5-10 IBU may inhibit souring. Souring time can vary depending on IBU level <ref>[https://omegayeast.com/yeast/bacterial-cultures/pediococcus Pediococcus OYL-606. Omega Yeast Labs website. Retrieved 06/11/2019.]</ref>. EPS production is unknown and has not been observed or reported <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/11709804795968312719576444737219/?comment_id=1171066879588191&reply_comment_id=1171595552868657&total_comments=62719963548031842&comment_tracking=%7B%22tn%22%3A%22R922R%22%7D Conversation with Richard Priess regarding WL Adi Hastings. Milk The Funk Facebook group on OYL Pediococcus EPS production. 06/11/2019.]</ref>. Commercial pitches only.|-| [[Propagate Lab]] || MIP-920 || ''P. damnosus'' || Will sour a finished beer over time to a pH of 3.5 - 3.1. It works well at room temperature and Wyeast homebrew pitchesis hop tolerant. It may produce ropiness <ref>[http://www.propagatelab.com/mip-920pediodamn Propagate Labs website. MIP-920. 10Retrieved 06/3020/20152020.]</ref>.

| [[WyeastRVA Yeast Labs]] || 5733 RVA 601 || damnosus (previously listed as ''P. cerevisiaedamnosus'') || May cause “ropiness” Lactic acid bacteria used in souring Belgian-style beers such as gueze and produce low levels of diacetyl Lambic. Acid production increases with extended storage time. Temp Temperature range: is 60-95° F (15-35° C). Cell count: 1.0 x 10⁸ (100 million) cells/mL <ref>[https://drive.google.com/folderview?id=0B8CshC9nxYHdZmE4MmoyLXA2WVk&usp=sharing Wyeast Specifications 2015 Retail Products. 2015.]</ref>. Homebrew packs contain 100-125 mL of slurry, and ~10-12.5 billion cells <ref name="priess_pitches"></ref>95°F.

| [[RVA Yeast White Labs]] || RVA 601 WLP661 || ''P. damnosus '' || Lactic acid bacteria used in souring BelgianHigh diacetyl (a.k.a. butter) producer and slow growing. Fermentation temp: 70-style beers such as gueze 85°F (21-29.4° C). Attenuation: 65%. Cell count: 50-80 million cells/mL <ref name="WL_cellcounts">Private correspondence with White Labs Customer Service and LambicDan Pixley. Acid production increases 10/29/2015.</ref>. Homebrew vials contain 35 mL of slurry, and ~1.75-2.8 billion cells per vial <ref name="priess_pitches">[https://www.facebook.com/groups/MilkTheFunk/permalink/1170980479596831/?comment_id=1171066879588191&reply_comment_id=1171595552868657&total_comments=6&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with storageRichard Priess regarding WL and Wyeast homebrew pitches. 10/30/2015. Temperature range is 60-95º F]</ref>.

| [[Inland Island Brewing & ConsultingWyeast]] || INISBC-998 5733 || ''P. damnosus '' (previously listed as ''P. cerevisiae'') || Gram positive cocci that produces lactic acid. Also produces May cause “ropiness” and produce low levels of diacetyl and several proteins that may cause a "rope" to form in the beer. Rope will disappear with extended storage time. Oxygen and hop sensitive Temp range: 60-95° F (15-35° C). Cell count: 1.0 x 10⁸ (100 million) cells/mL <ref>[https://drive.google.com/folderview?id=0B8CshC9nxYHdZmE4MmoyLXA2WVk&usp=sharing Wyeast Specifications 2015 Retail Products. 2015.]</ref>. 75Homebrew packs contain 100-125 mL of slurry, and ~10-90°F Temperature Range12.5 billion cells <ref name="priess_pitches"></ref>.

[[File:Pedio sugarsEMP Pathway.JPGjpg|thumb|300200px|Pedio fermentables <ref>Wine Microbiologyright|[https://onlinelibrary. Practical Applications and Procedureswiley.com/doi/full/10. Kenneth C1111/ajgw. Fugelsang12366 Homofermentative Embden–Meyerhof–Parnas (EMP) pathway for the production of lactic acid, acetoin, Charles Gdiacetyl and 2,3‐butanediol and acetic acid production from citrate metabolism. EdwardsImage by Wade et al (2018).</ref>]]]

About 90% of sugar metabolized by ''Pediococcus'' produces both L- and D-lactic acid<ref name="Wade_2018" />. It does so by homolactic fermentation producing primarily lactic acid (same EMP pathway as [[Lactobacillus#Types_of_Metabolism|''Lactobacillus'' homolactic fermentation]]), although some species/strains can convert glycerol to lactic acid, acetic acid, acetoin, and CO2 under aerobic conditions (''P. damnosus'' is not in this category) <ref>[https://books.google.com/books?id=1b1CAgAAQBAJ&pg=RA2-PA1&lpg=RA2-PA1&dq=pediococcus+damnosus+homolactic&source=bl&ots=myI2alVB78&sig=cG-yWB4GuABQFEtqD2CAyKmU0TE&hl=en&sa=X&ved=0CEAQ6AEwBGoVChMI66C5593-xgIVCVKICh3Pcg7c#v=onepage&q=pediococcus%20damnosus%20homolactic&f=false Encyclopedia of Food Microbiology. Pediococcus. Carl A. Batt. Academic Press, Sep 28, 1999 .]</ref>. Some strains of ''P. damnosuspentosaceus'' can ferment glucose, sucrose, five-chain sugars such as xylose to produce acetic acid and galactoselactic acid. Some strains of ''P. damnosushalophilus'' (now reclassified as ''Tetragenococcus halophilis'' ) can ferment maltose convert citric acid into acetic acid and oxaloacetate (oxaloacetate is then further reduced to acetic acid and diacetyl, and the diacetyl is further reduced to acetoin, and 2,3-butanediol) by producing citrate lyase enzyme. This generally occurs at a slower rate than malolactic fermentation and depends on pH and sucrose temperature. However, all species in the ''Pediococcus'' genus are considered obligatory homofermentative because of the pathways that they use <ref name="ucdavis">[http://aem.asm.org/content/81/20/7233.full A Genomic View of Lactobacilli and pediococci Demonstrates that Phylogeny Matches Ecology and Physiology. Jinshui Zheng, Lifang Ruan, Ming Sun and Michael Gänzle. 2015.]</ref>. The disaccharide trehalose is the preferred carbon source for Pediococci <ref name="GeisslerWade_2018"/><ref>[https://aem.asm.org/content/53/6/1257.short Citrate Metabolism by Pediococcus halophilus. Chiyuki Kanbe, Kinji Uchida. 1987.]</ref>.

===Growth Diacetyl and EnvironmentAcetoin===''P. damnosus'' is sensitive to temperature can produce high amounts of diacetyl and pHacetoin during lactic acid production <ref>[http://onlinelibrary. It is unable to grow at a pH wiley.com/doi/10.1046/j.1365-2672.2000.00956.x/pdf Identification of 8 or higher or at 35°Cpediococci by ribotyping. The optimal growth occurs at 22°C R. Satokari, T. Mattila-Sandholm and 5M.5 pHL. ''PSuihko. damnosus'' is sensitive to environments that contain NaCl Journal of Applied Microbiology 2000, 88, and will not grow with concentrations of 4% NaCl 260–265.]</ref><ref name="ucdavis">[http://mmbr.asm.org/content/77/2/157.full The Microbiology of Malting and Brewing. Nicholas A. Bokulicha, and Charles W. Bamforth. June 2013.]</ref>. Most strains of Diacetyl is the 'buttery'P. claussenii'' can grow aroma and flavor found in beer(generally not favorable) and in wine (favorable in amounts between 1-4 mg/L). About half of the strains tested of ''P. damnosus'' can grow While other microbes found in beer, and none to very few strains of wine fermentation (namely ''P. acidilacticiSaccharomyces cerevisiae'') can also produce diacetyl, ''P. parvulusPediococcus'', and ''P. pentosaceus'' have been found other lactic acid bacteria are known to be able to grow in finished beerproduce much higher amounts <ref name="Wade_2018" />.

One study showed that optimal growth was observed in [http://www.neogen.com/Acumedia/pdf/ProdInfo/7406_PI.pdf MRS media] with an initial pH In lactic acid bacteria, diacetyl can be the byproduct of both homofermentative metabolism of sugars as well as the metabolism of 6.7citric acid, and it is a final pH way for the cells to regenerate NADP⁺. In either of 4.14these two pathways, extra pyruvate is turned into alpha-acetolactate which occurred naturally from fermentationthen undergoes an oxidative decarboxylation reaction to produce diacetyl. The addition of bacteriological peptoneDiacetyl is often reduced by yeast to acetoin and/or 2, MnSO43-butanediol, which have a higher threshold and Tween 80 also increased activityless of an impact on the finished beer/wine <ref name="Wade_2018" />. Maximum cell densities In mixed fermentation sour beer, the breakdown of diacetyl into acetoin and 2,3-butanediol is often thought to be carried out by ''Brettanomyces'' in a similar way to ''P. damnosusSaccharomyces'' species, but this has not been investigated that we are around 1-2 billion cells/mL in MRS media aware of . It has been reported that diacetyl reduction is faster at a lower pH of 6around 3.7 ''(editor's note: this maximum cell density number needs 5, which is a typical pH range for sour beer and might be one of the contributing factors to be verified)'' a lack of anecdotal reports of diacetyl in sour beer <ref>[httphttps://wwwonlinelibrary.wiley.com/doi/full/10.1002/jib.381 Michel, M.ncbi, Meier‐Dörnberg, T.nlm, Jacob, F.nih, Methner, F.gov/pubmed/11851822 Growth optimization of Pediococcus damnosus NCFB 1832 and the influence of pH and nutrients on the production of pediocin PD-1‐J. Nel HA, Bauer Wagner, R. S., and Hutzler, Vandamme EJM. (2016) Review: Pure non‐Saccharomyces starter cultures for beer fermentation with a focus on secondary metabolites and practical applications. J. Inst. Brew., Dicks LM122: 569– 587. 2001doi: 10.1002/jib.381.]</ref>, but this is only in optimal conditions. Maximum cell density varies based on the conditions of the propagation with pH and nutrient demands being two of the main limiting factors <refname="krogerus_2013">[https://www.redditresearchgate.comnet/rpublication/Homebrewing259331290_125th_Anniversary_Review_Diacetyl_and_its_control_during_brewery_fermentation Krogerus, K. and Gibson, B.R. (2013), 125th Anniversary Review: Diacetyl and its control during brewery fermentation. J. Inst. Brew., 119: 86-97. https:/comments/3qp7b7doi.org/advanced_brewers_round_table_neva_parker_white10.1002/cwh7iqq Neva Parker, Reddit threadjib. 10/29/201584.]</ref>.

Although more experiments are probably neededSeveral variables the affect diacetyl and acetoin production have been identified. First of all, agitation is believed to be an important factor for any some strains of ''Pediococcus'' species of microbe (yeast produce diacetyl, and bacteria)others do not. Gentle stirring on a stir plate or orbital shakerDuring malolactic fermentation (conversion of citric acid to lactic acid), the temperature at which MLF is conducted can influence whether or frequent gentle manual agitation leads to faster growth and a higher number of organismsnot diacetyl is produced. Agitation keeps For example, two studies reported that more diacetyl and acetoin were produced during the microbes MLF in solutionwine at 18°C compared at 25°C. It also maximizes The effect of temperature is not well understood, but it has been hypothesized that it could be that at lower temperature yeast is less active and thus cannot break the microbes' access diacetyl down to acetoin and 2,3-butanediol (extended time exposed to nutrients active yeast or on lees can reduce diacetyl in wine and disperses waste evenlyprobably also beer). In If SO₂ is used, it can bind to diacetyl in a non-agitated starterform that cannot be tasted, although the microbes are limited to the diffusion rate of nutrients, leading to a slower and more stressful growth SO<refsub>[https://www.facebook.com/groups/MilkTheFunk/permalink/1168024059892473/?comment_id=1174865305875015&reply_comment_id=1176092372418975&total_comments=1&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with Bryan of Sui Generis Blog about starters and agitation. 11/09/2015.]2</refsub>can become unbound and release the diacetyl again. Although ''Pediococcus'' are generally considered facultative anaerobes and oxygen usually does not negatively affect their growth, some strains may show less growth An increase in the presence of oxygen and are considered anaerophilic, meaning that the presence of oxygen inhibits their growth (and therefore their citric acid production) can also lead to more diacetyl under semi-aerobic conditions but they can still grow in the presence of O2not anaerobic conditions. The presence of CO2 glucose has a positive effect on acid also been associated with higher levels of diacetyl production in wine <ref name="NAKAGAWAWade_2018"></ref> . Therefore, it is generally best practice to seal the starter with an airlock.

Some strains of It has been observed that ''P. damnosusLactobacillus'' species can cause a beer produce EPS (or wine''Lactococcus lactis'', ''Lactobacillus delbrueckii'', ''Lactobacillus casei'', and ''Lactobacillus helveticus'') to go <ref name="ropyESP"></ref>. Reportedly, ropiness in beer that also has Some ''BrettanomycesOenococcus oeni'' (which is traditionally credited with breaking down the ropiness after a period of rest) usually lasts anywhere from 1 week to 3 months, although fewer reports claim that it has lasted as long as 7 months (see reference for different experiences of brewers) strains can also produce EPS <ref>[https://wwwpubmed.ncbi.nlm.facebooknih.comgov/groups19659698/MilkTheFunk/permalink/1132030550158491/ Poll on Milk The Funk regarding how long Ciezack G, Hazo L, Chambat G, Heyraud A, Lonvaud-Funel A, Dols-Lafargue M. Evidence for exopolysaccharide production by Oenococcus oeni strains isolated from non-ropy beer has been observedwines. J Appl Microbiol. 2010 Feb;108(2):499-509. doi: 10. 081111/20/2015j.1365-2672.2009.04449.x. Epub 2009 Jun 30. PMID: 19659698.]</ref>. This "ropiness" is actually caused by production Some species of exopolysaccharides (yeast can also produce EPS) in the form of β-glucans (beta glucans). A small amount of β-glucan is adequate enough to affect the visible viscosity of beer or wine. The gene known as "dps" has been identified with the production of β-glucan/EPS in , including ''P. damnosusCandida'', and the gene "gtf" in ''P. clausseniiCryptococcus'' <ref name="Snauwaert"></ref>. , Not all strains of ''P. damnosusDebaryomyces'' express the gene, and only ones that do will cause a beer to go ropy. Although it is not needed to survive in beer''Lipomyces'', EPS production is probably has importance in biofilm production ''Pichia'' <ref>[httphttps://catwww.inistfacebook.frcom/groups/?aModele=afficheN&cpsidt=23890699 Ethanol tolerance of lactic acid bacteria, including relevance of MilkTheFunk/permalink/2465980936763439/ Zach Taggart. Milk the exopolysaccharide gene gtf. Pittet V, Morrow K, Ziola BFunk Facebook group post on EPS from yeast. 201101/16/2019.]</ref>, and ''PediococciPseudozyma'' that are ropy have been found to be more acid, alcohol, ''Rhodotorula'' and SO2 tolerant than other ''PediococciSporobolomyces''. The thickness of the ropiness is increased with the presence of malic acid <ref name="ESPGientka_2015">[https://www.researchgate.net/publication/283498621_Exopolysaccharides_from_yeast_insight_into_optimal_conditions_for_biosynthesis_chemical_composition_and_functional_properties_-_review?fbclid=IwAR1X6Y0rnquoF6SD-eH9m6EWpLIefgZJFUJK51NJYBooJWngxEVS2aR3PKE Exopolysaccharides from yeast: insight into optimal conditions for biosynthesis, chemical composition and functional properties - review. Iwona Gientka, Stanisław Błażejak, Stanisław Błażejak, Lidia Stasiak, Lidia Stasiak, Anna Chlebowska-Śmigiel, Anna Chlebowska-Śmigiel. 2015.]</ref>.

One study showed that the production of β-glucan coincided with the end of the growth phase of ''Pediococcus''====Videos====* [https://www. While small amounts of β-glucan were produced during growth, after 2 days of growth, β-glucan production increased as growth slowedfacebook. β-glucan production stopped when growth stopped. This study showed that β-glucan production is linked to ''Pediococcous'' growth, producing more towards the end of growth. This would explain why com/groups/MilkTheFunk/permalink/4547361381958707/ Highly viscous ropy beer containing ''Pediococcus'' often goes ropy shortly after naturally carbonating video posted in the bottleMTF by Roi Funk Krispen. This study found that other variables were not factors in the production of β-glucan, such differing levels of alcohol (although alcohol interacts with the β-glucan in a way that makes the viscosity seem thicker)]* [https://www. The study also found that the lack of agitation increased the β-glucan production (wine makers will often agitate or aerate ropy wine to cure the wine from ropiness)facebook. A higher com/groups/MilkTheFunk/permalink/3478055812222608/ Post on MTF by Brandon Jones showing initial pH encourages higher growth (5.5+)ropiness of a beer, which increases β-glucan production. A lower initial pH (3.5), decreases growth and β-glucan productionthen after aging the ropiness out for 8 weeks. A higher concentration of glucose increased growth and β-glucan production]* [https://www. A low starting pH decreases growth, and therefore decreases β-glucan productionfacebook. Glocuse is needed for β-glucan production. While fructose alone is mostly insufficient, a combination com/groups/MilkTheFunk/permalink/1813022388725967/ Other videos on MTF of glucose and fructose was slightly more efficient than glucose alone <ref name="ESP"></ref>ropy beer.]

It has ===Bacteriocins===Some strains of ''Pediococcus pentocaseus'' have been observed found to produce bacteriocins, which are toxins that are produced by the cells that inhibit the growth of other types of bacteria. For example, Bootleg Biology's "Sour Weapon" culture produces antimicrobials called bacteriocins or pediocins (see Bootleg Biology's [https://www.facebook.com/BootlegBiology/photos/a.148869931970401.1073741829.124634287727299/465185997005458/?type=1&theater Facebook post] regarding bacteriocins for more info). These can inhibit and kill similar species of bacteria like ''Lactobacillus'' and other ''Pediococcus'' species in mixed-culture fermentations. Bacteriocin production can be higher when ''Pediococcus pentocaseus'' is co-fermented with other bacteria than when it is fermented on its own <ref>[https://www.frontiersin.org/articles/10.3389/fmicb.2018.02952/abstract Enhanced Bacteriocin Production by Pediococcus pentosaceus 147 in Co-Culture with Lactobacillus plantarum LE27 on Cheese Whey Broth. Carolina Gutiérrez-Cortés, Héctor Suarez, Gustavo Buitrago, Luis A. Nero and Svetoslav D. Todorov. 2018. DOI: 10.3389/fmicb.2018.02952.]</ref>. A strain of ''Pediococcus pentocaseus'' was found to produce EPS (a "class II" enteriocin that inhibits the growth of ''Lactococcus lactisE. coli'', and ''Lactobacillus delbrueckiiStaphylococcus aureus''<ref>[https://www.sciencedirect.com/science/article/pii/S0882401017314559 Antibacterial activity of Lactobacillus plantarum isolated from Tibetan yaks. Lei Wang, Hui Zhang, Mujeeb Ur Rehman, Khalid Mehmood, Xiong Jiang, Mujahid Iqbal, Xiaole Tong, Xing Gao, Jiakui Li. 2017.]</ref>. ''Lactobacillus caseiP. damnosus''also produces an antimicrobial compound called pediocin PD-1, and which can inhibit several bacteria spp including ''Lactobacillus helveticusO. oeni'') <ref name="ESP">[http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2672.2001.01486.x/full Growth optimization of Pediococcus damnosus NCFB 1832 and the influence of pH and nutrients on the production of pediocin PD-1. H.A. Nel1, R. Bauer, E.J. Vandamme and L.M.T. Dicks. Jan 2002.]</ref><ref>[http://www.ncbi.nlm.nih.gov/pubmed/15878403 Purification, partial amino acid sequence and mode of action of pediocin PD-1, a bacteriocin produced by Pediococcus damnosus NCFB 1832. Bauer R, Chikindas ML, Dicks LM. May 2005.]</ref>.

See also:* [[File:EPSLactobacillus#Bacteriocins|''Lactobacillus'' bacteriocins]].gif ===Malolactic Fermentation===See the [[Cider#Microbes|thumb|300|Exopolysaccharide pathway Cider]] page. ===Biogenic Amines===Biogenic amines are produced by all living things and are present in many fermented beverages. High dosages can lead to health issues such as vomiting, headache, asthma, hypotension, and cardiac palpitation. Thus, biogenic amines have been studied intensely <ref name="ESPWade_2018"/>. For more information on biogenic amines in beer in general, see [http://wwwsuigenerisbrewing.sciencedirectcom/index.comphp/2019/science01/article22/piibiogenic-amines/S0740002004000668 Glucose fermentation kinetics and exopolysaccharide production "Fact or Fiction – Biogenic Amines in Beer" by ropy Pediococcus damnosus IOEB8801Dr. Emilie Walling, Marguerite Dols-Lafargue, Aline Lonvaud-FunelBryan Heit]. Food Microbiology Volume 22, Issue 1, January 2005, Pages 71–78.]</ref>]]

===Other Metabolites===Some strains of lactic acid bacteria, including ''P. damnosusPediococcus'' , can produce high amounts of diacetyl during lactic acid production metabolize amino acids into biogenic amines, and potentially also degrade them <ref>[httphttps://onlinelibrarywatermark.wileysilverchair.com/doi/10.1046/j.13650362-028x-2672.2000.0095660_7_831.x/pdf Identification of pediococci Tyramine Formation by ribotypingPediococcus spp. Rduring Beer Fermentation. SatokariMARIA IZQUlERDO-PULIDO, T. MattilaJOSEP-MIQUEL CARCELLER-ROSA, ABEL MARINE-Sandholm FONT, and M.L. SuihkoCARMEN VIDAL-CAROU. Journal of Applied Microbiology 2000, 88, 260–2651996.]</ref><ref>[httphttps://mmbrwww.asmresearchgate.org/content/77net/2publication/157.full The Microbiology 240429641_Effect_of_tyrosin_on_tyramin_formation_during_beer_fermentation Effect of Malting and Brewingtyrosin on tyramin formation during beer fermentation. Nicholas A. BokulichaMaria Izquierdo-Pulido, and Charles WM. BamforthCarmen Vidal-Carou. June 20132000.]</ref>. ''PThe number of strains capable of producing biogenic amines appears to be very low. damnosus'' also produces an antimicrobial compound called pediocin PD-1, which can inhibit several bacteria spp including ''O. oeni'' <ref> [httphttps://onlinelibrarylink.wileyspringer.com/doi/10.1046/j.1365-2672pdf%2F10.2001.01486.x/full Growth optimization of Pediococcus damnosus NCFB 1832 1007%2FBF01105812 Weiller and the influence Radler (1976)] found that only one out 28 strains of pH and nutrients on the production of pediocin PD-1''P. Hcerevisiae'' (later reclassified to ''P.A. Nel1, R. Bauer, E.J. Vandamme damnosus'' and L''P.M.T. Dickspentosaceus'') produced biogenic amines. Jan 2002.]</ref><ref>[httphttps://www.ncbi.nlm.nih.gov/pubmed/15878403 Purification, partial amino acid sequence and mode 973463 Strickland et al. (2016)] found that out of action multiple species of pediocin PD-1, a bacteriocin produced by Pediococcus damnosus NCFB 1832. Bauer R, Chikindas ML, Dicks LM. May 2005.]</ref>. ''P. clausseniiPediococcus'' tends to produce a smaller amount , only one strain of acetic acid than lactic acid in about a 1:3 ratio. ''P. damnosusinopinatus'' tends to produce produced biogenic amines, and it only lactic acid and no acetic acid <ref name="Geissler">produced 3.3 mg/L of histamine. [httphttps://www.sciencedirect.com/science/article/pii/S0168160515301033 Metabolic strategies S0168160511002893 García‐Ruiz et al. (2011)] reported that 9 out of 85 strains of beer spoilage lactic acid bacteria in beer''P. Andreas Jparvulus'' and ''P. Geisslerpentosaceus'' were able to degrade some biogenic amines (histamine, tyrosine, and putrescine) in culture media, Jürgen Behrbut were unable to do so in wine, Kristina von Kampindicating that any degradation of biogenic amines in wine that might occur is not likely due to lactic acid bacteria, Rudi F. Vogel. 2015.]but due to some other cause <ref name="Wade_2018" /ref>.

===Mixed Culture Influence===:Izquierdo-Pulido et al. (1995) found that out of 35 samples of Spanish lagers contaminated with ''Pediococcus'Editor's note: special thanks , 21 of them had final tyramine levels between 5-10 mg/l, 6 of them had no detected tyramine, and 8 of them had high levels around 25 mg/l, with higher levels being correlated to Richard Preiss higher cell counts of ''Pediococcus''. higher levels of tyramine were associated with higher cell counts of the tyramine-producing strains during smaller bench test fermentations as well. There was no correlation between the presence of wild yeast and tyramine production. Filtration and pasteurization after fermentation had no effect on the levels of tyramine in the final beers <ref>[[Escarpment Laboratorieshttps://watermark.silverchair.com/0362-028x-59_2_175.pdf Biogenic Amine Changes Related to Lactic Acid Bacteria During Brewing. MARIAI ZQUIERDO-PULIDO, JUDIT FONT-FABREGAS, JOSEP-MIQUEL CARCELLER-ROSA, ABEL MARINE-FONT, and CARMENVIDAL-CAROU. 1995.]] for helping to interpret the science referenced this section</ref>.''

De Roos et al (2024) found the ''P. damnosus'', as well as some other bacteria, have been shown to alter the expression in two samples of genes in most, but not all, ''Saccharomyces cerevisiae'' strains (and other ''Saccharomyces'' species and even perhaps [[Brettanomyces]]), in a way that changes how they ferment sugars, and essentially forms a symbiotic environment with lambic had the yeastgenetic capability to produce histamine. Normally ''Saccharomyces'' will only ferment glucose when glucose is present and ignores other sugars such as maltose and maltotriose until the glucose is gone. Biologically speaking, when the presence The total biogenic amine content of glucose in the yeast's environment shuts down the yeast's ability to ferment any other types of sugar besides glucose, this is called "glucose repression" lambic was at levels below that which has been deemed safe by European regulatory bodies <ref name="cross-kingdom">[http://weitzlab.seas.harvard.edu/files/weitzlab/files/2014_cell_jarosz.pdf Cross-Kingdom Chemical Communication Drives a Heritable, Mutually Beneficial Prion-Based Transformation of Metabolism. 2014. Daniel F. Jarosz, Jessica C.S. Brown, Gordon A. Walker, Manoshi S. Datta, W. Lloyd Ung, Alex K. Lancaster, Assaf Rotem, Amelia Chang, Gregory A. Newby,David A. Weitz, Linda F. Bisson, and Susan Lindquist. Cell. 2014 Aug 28;158(5):1083-93.]</ref>. ''Saccharomyces'' and ''Brettanomyces bruxellensis'' (it is currently not known if other ''Brett'' species other than ''B. bruxellensis'' have this ability) have a gene called "GAF+" that when expressed actually allows it to bypass this "glucose repressionRoosa_2024" and ferment the other sugars simultaneously. Normally this gene is not expressed except by a very small number of cells <ref>[http://www.cell.com/cell/abstract/S0092-8674(14)00974-X An Evolutionarily Conserved Prion-like Element Converts Wild Fungi from Metabolic Specialists to Generalists. Daniel F. Jarosz, Alex K. Lancaster, Jessica C.S. Brown, Susan Lindquist. Cell. Volume 158, Issue 5, p1072–1082, 28 August 2014]</ref>.

When ''PSee also:* [[Spontaneous_Fermentation#Biogenic_Amines|Biogenic amines in spontaneously fermented beer. damnosus'' lives together with ]]* [[Brettanomyces#Biogenic_Amines|Biogenic amine production by ''SaccharomycesBrettanomyces'', a chemical is produced by ''P. damnosus'' that essentially "turns on" the GAF+ gene ]]* [[Wine#Biogenic_Amines|Biogenic amines in ''Saccharomyces''wine.]]* [http://www. Not only does ''Saccharomyces'' then have the ability to ferment other sugars at the same time as glucose, but it produces less alcoholhorscategoriebrewing. Viability over time is also increased in ''Saccharomyces'' cells that express this gene versus those that don'tcom/2019/01/spontaneous-fermentation-and-biogenic. In wild html "Spontaneous fermentation and biogenic amines" by Dr. Dave Janssen; review of grapes, the wild GAF+ ''Saccharomyces'' strains thrived over the other types of fungi several studies that were found on looked at the wild grapes. This led the researchers levels of the referenced study to speculate that the GAF+ gene may play a role biogenic amines in preventing other fungi from thriving. It is thought that this benefits both microorganisms, which are often found together in the wild during fermentation of fruit; the bacteria isn't killed by higher alcohol levelsdifferent beers and their production, and the yeast has a broader food sourcetheir potential flavor contribution. Furthermore, once a ''Saccharomyces'' cell expresses the gene, it will continue to pass this gene expression onto its offspring]* [http://suigenerisbrewing. In winemaking, this is the cause of arrested wine fermentations due to the lower amount of alcohol producedcom/index. For example in the referenced study, the GAFphp/2019/01/22/biogenic- ''Saccharomyces'' cells fermented grape must into a 12% ABV wine, and the GAF+ ''Saccharomyces'' cells fermented the same wine must into an 8% ABV wine <ref name=amines/ "cross-kingdomFact or Fiction – Biogenic Amines in Beer"></ref>by Dr. However, the implications Bryan Heit; an analysis of this biogenic amines in sour spontaneously fermented beer brewing are much different and have yet associated health concerns.]** [https://www.facebook.com/groups/MilkTheFunk/permalink/2570617069633158/?comment_id=2570641549630710&reply_comment_id=2570664762961722&comment_tracking=%7B%22tn%22%3A%22R8%22%7D Follow up from Dr. Heit on MTF on "allergic-like" reactions to be explored scientificallybiogenic amines.]

Of all the ===Other Metabolites===''LactobacillusP. claussenii'' species that have been studied for this behavior (tends to produce a smaller amount of acetic acid than lactic acid in about a 1:3 ratio. ''LP. brevisdamnosus''tends to produce only lactic acid and no acetic acid <ref name="Geissler">[http://www.sciencedirect.com/science/article/pii/S0168160515301033 Metabolic strategies of beer spoilage lactic acid bacteria in beer. Andreas J. Geissler, Jürgen Behr, Kristina von Kamp, ''LRudi F. Vogel. 2015. hilgardii'']</ref>, ''Lalthough some strains have been found to produce small amounts of acetic acid of around 100-300 ppm. This level is slightly below and above flavor thresholds in lager beer (but could be additive with other organisms) <ref>[http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.2010.tb00393. plantarum''x/abstract Isolation, Identification, and ''LCharacterisation of Beer-Spoilage Lactic Acid Bacteria from Microbrewed Beer from Victoria, Australia. kunkeei'') Garry Menz, Christian Andrighetto, Angiolella Lombardi, Viviana Corich, Peter Aldred, only ''LFrank Vriesekoop. 2010. kunkeei'' was shown to induce ]</ref>, but significantly less than the GAF+ genetotal acetic acid often found in gueuze (around 700-2200 ppm <ref>[http://www.horscategoriebrewing.com/2016/07/duivelsbier-of-halle.html Jansen, Dave. Some species Hors Category Blog. "Duivelsbier of Halle". 07/30/2016. Retrieved 01/31/2018.]</ref>) and Flanders reds (300-2300 ppm <ref>[http://www.sciencedirect.com/science/article/pii/S0168160515301896 Microbial diversity and metabolite composition of bacteria from the genres ''Staphylococcus''Belgian red-brown acidic ales. Isabel Snauwaert, ''Micrococcus''Sanne P. Roels, ''Bacillus''Filip Van Nieuwerburg, ''Listeria''Anita Van Landschoot, ''Paenibacillus''Luc De Vuyst, Peter Vandamme. 2015.]</ref>). ''GluconobacterPediococcus'', also carries the decarboxylase enzyme (PAD) which converts hydroxycinnamic acid (ferulic acid) into phenols (4-vinyl guaiacol) <ref name="lentz_2018">[http://www.mdpi.com/2311-5637/4/1/20/html#B13-fermentation-04-00020 The Impact of Simple Phenolic Compounds on Beer Aroma and Flavor. Michael Lentz. 2018. doi: 10.3390/fermentation4010020.]</ref>. While ''SinorhizobiumPediococcus''has been linked to the creation of acrolein via the metabolism of glycerol, evidence supports that this is very rare in ''EscherichiaPediococcus''species. In wine, acrolein reacts with anthocyanins and other phenols to produce an intense bitterness. Acrolein production in wine has been linked to some strains of ''SerriatiaLactobacillus'', and all . Some strains of ''Pediococcus'' species tested also influenced have been found to metabolize gylcerol in beer and wine under aerobic and semi-aerobic environments, but the GAF+ gene metabolism of glycerol in ''Saccharomyces'' the presence of oxygen results in the production of lactic acid, acetic acid, diacetyl, and 2,3-butanediol, and not acrolein <ref name="cross-kingdomWade_2018"></ref>.