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[[File:Pedio.jpg|thumb|200px|right|[https://www.instagram.com/wildandsour/ Pediococcus - picture taken by Per Karlsson]]]
'''''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. 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]]) <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 exopolysaccharides when 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]]'', [[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 CO<sub>2</sub>, ethanol, or acetic acid, although there are a few exceptions to this in the literature. They do not produce [https://onlinelibraryen.wileywikipedia.comorg/wiki/doiCatalase catalase] (except for some ''P. pentocaseus'' strains which were reported to have pseudo-catalase activity by Simpson and Taguchi 1995) or [https:/full/10en.wikipedia.1111org/wiki/ajgwOxidase oxidase] enzymes.12366 Role Because of Pediococcus the way that ''Pedioccous'' cells divide, they often appear stuck together in winemakingpairs or clumps. MThey 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.EWhen grown on agar that is supplemented with 100 mg/L of pimaricin, the colonies are white-grey with a diameter of about 1 mm. WadeRopy strains have a high elasticity, and when touched with a needle, Mlong threads can be drawn and sometimes the colonies completely stick to the needle.T See [https://onlinelibrary. Strickland, Jwiley.Pcom/doi/full/10. Osborn, C1111/ajgw.G12366 table 2 from Wade et al. Edwards. (2018. DOI: )] 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.org1094/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: 10.11111094/ajgw.12366ASBCJ-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''.]
==Commercial Pediococcus Cultures==
! Name !! Mfg# !! Taxonomy !! Note
|-
| [[Bootleg Biology]]/[[Spot Yeast]] || Sour Weapon P (''Pediococcus pentosaceus'' Blend) || ''P. pentosaceus'' blend || 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 a pH of 3.5 within 24 hours. With more time, a terminal pH of 3.1 may be reached. ''P. pentosaceus'' can also be used for long-term sours. It is capable of growing and producing 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. At ~30 IBU, souring occurs in 2-3 months <ref>[https://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-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 (exopolysaccharides) have occurred in testing <ref>[http://bootlegbiology.com/product/sour-weapon-pediococcus-pentosaceus-blend/ Bootleg Biology website. Retrieved 05/06/2016.]</ref>. It is still unknown how hops will affect souring in a long term scenario. Bootleg 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://www.eastcoastyeast.com/wild-stuff.html "Wild Yeast / Brettanomyces / 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="Amaral_Mainiacal">Private correspondence with Justin Amaral by Dan Pixley. 01/24/2018.]</ref>. Commercial pitches only.|-| [[Mainiacal Yeast]] (CLOSED) || MYPD1 || ''P. damnosus''|| Isolated from a bottle of belgian lambic. Produces diacetyl and EPS, so use in conjunction with ''Brettanomyces''. Ferment at 70-90°F <ref name="Amaral_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/2719576444737219/?comment_id=2719963548031842&comment_tracking=%7B%22tn%22%3A%22R%22%7D Adi Hastings. Milk The Funk Facebook group on OYL Pediococcus EPS production. 06/11/2019.]</ref>. Commercial pitches only.
|-
| [[Mainiacal YeastPropagate Lab]] || MYPD1 MIP-920 || ''P. damnosus'' || Isolated from Will sour a bottle finished beer over time to a pH of belgian lambic3.5 - 3.1. Produces diacetyl It works well at room temperature and EPS, so use in conjunction with ''Brettanomyces''is hop tolerant. It may produce ropiness <ref>[http://www.propagatelab.com/mip-920pediodamn Propagate Labs website. Ferment at 70MIP-90°F 920. Retrieved 06/20/2020.]</ref name="Amaral_Mainiacal" />. '''Commercial pitches only'''.
|-
| [[RVA Yeast Labs]] || RVA 601 || ''P. damnosus'' || Lactic acid bacteria used in souring Belgian-style beers such as gueze and Lambic. Acid production increases with storage. Temperature range is 60-95°F.
===Manufacturer Tips===
====[[Bootleg Biology]] on Sour WeaponP====This product, which is a blend of ''Pediococcus pentosaceus'', can be used for a kettle souring process or a mixed fermentation process. Jeff reported good growth results using 2 grams of calcium carbonate (chalk; CaCO3) per liter of wort for starters of Sour Weapon <ref name="mello_starter">[https://www.facebook.com/groups/MilkTheFunk/permalink/1369904163037794/?comment_id=1370329352995275&reply_comment_id=1370751796286364&comment_tracking=%7B%22tn%22%3A%22R5%22%7D Conversation on MTF with Jeff Mello regarding starters for Pediococcus. 08/08/2016.]</ref>. This same formula might benefit other ''Pediococcus'' starters as well. The CaCO3 serves as a buffering agent that keeps the starter pH from getting too low too fast, and is similar to the concept of buffered growth media for ''Lactobacillus'' (see [[Lactobacillus#Samuel_Aeschlimann.27s_Starter_Procedures|''Lactobacillus'' Starter]]).
Regarding exposure to oxygen in general:
==Metabolism==
===Lactic Acid ProductionGrowth and Environment===''Pediococcus'' generally has a high tolerance to ethanol compared to other bacteria, and can range from 10-25% ABV, depending on the species and strain. ''P. damnosus'' is sensitive to warm temperatures. It is unable to grow at 35°C or higher. The optimal growth occurs at 22°C. Other species can be more tolerant of higher temperatures, for example, ''P. parvulus'' and ''P. inopinatus'' have been shown to grow between 12 to 40°C, with rapid death occuring at 45°C <ref name="Wade_2018" />. ''P. damnosus'' is sensitive to environments that contain NaCl, and will not grow with concentrations of 4% NaCl <ref name="ucdavis"></ref>. Most strains of ''P. claussenii'' can grow in beer. About half of the strains tested of ''P. damnosus'' can grow in beer, and none to very few strains of ''P. acidilactici'', ''P. parvulus'', and ''P. pentosaceus'' have been found to grow in finished beer. Another environmental factor that can affect the growth and survival of ''Pediococcus'' is pH. ''P. damnosus'' is unable to grow at a pH of 8 or higher. One study showed that optimal growth for ''P. damnosus'' was observed in [http://www.neogen.com/Acumedia/pdf/ProdInfo/7406_PI.pdf MRS media] after ~84 hours with an initial pH of 6.7, and a final pH of 4.14, which occurred naturally from fermentation. The addition of bacteriological peptone, MnSO4, and Tween 80 also increased activity. Maximum cell densities of ''P. damnosus'' are around 4.3 billion cells/mL in MRS media starting at a pH of 5.5 <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1347683325259878/?comment_id=1349386438422900&reply_comment_id=1350340544994156&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Richard Preiss on MTF regarding Pediococcus cell density. 07/19/2016.]</ref><ref name="Nel">[http://www.ncbi.nlm.nih.gov/pubmed/11851822 Growth optimization of Pediococcus damnosus NCFB 1832 and the influence of pH and nutrients on the production of pediocin PD-1. Nel HA, Bauer R, Vandamme EJ, Dicks LM. 2001.]</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 <ref>[https://www.reddit.com/r/Homebrewing/comments/3qp7b7/advanced_brewers_round_table_neva_parker_white/cwh7iqq Neva Parker, Reddit thread. 10/29/2015.]</ref>. Although more experiments are probably needed, agitation is believed to be an important factor for any species of microbe (yeast and bacteria). Gentle stirring on a stir plate or orbital shaker, or frequent gentle manual agitation leads to faster growth and a higher number of organisms. Agitation keeps the microbes in solution. It also maximizes the microbes' access to nutrients and disperses waste evenly. In a non-agitated starter, the microbes are limited to the diffusion rate of nutrients, leading to a slower and more stressful growth <ref>[Filehttps:Pedio sugars//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.]</ref>. Although ''Pediococcus'' are generally considered facultative anaerobes and oxygen usually does not negatively affect their growth, some strains may show less growth in the presence of oxygen and are considered anaerophilic, meaning that the presence of oxygen inhibits their growth (and therefore their acid production) but they can still grow in the presence of O<sub>2</sub>.JPG The presence of CO<sub>2</sub> has a positive effect on acid production <ref name="NAKAGAWA"></ref><ref name="Oevelen_1979" />. Therefore, it is generally best practice to seal the starter with an airlock. ====Starter Information====General starter information for commercial ''Pediococcus'' cultures is limited. In addition to the various [[Pediococcus#Manufacturer_Tips|rightstarter suggestions by various labs]] regarding their individual cultures, Jeff Mello of Bootleg Biology reported good growth results when using 2 grams of calcium carbonate (chalk; CaCO3) per liter of wort for starters of Sour Weapon <ref name="mello_starter"></ref>. This same formula might benefit other ''Pediococcus'' starters as well. The CaCO3 serves as a buffering agent that keeps the starter pH from getting too low too fast, and is similar to the concept of buffered growth media for ''Lactobacillus'' (see [[Lactobacillus#Samuel_Aeschlimann.27s_Starter_Procedures|Pedio fermentables ''Lactobacillus'' Starter]]). Starters of ''P. damnosus'' cultures could require around 84 hours for optimal growth, however, this time requirement hasn't been looked at in wort starters (only MRS media) <ref name="Nel"></ref>. All species require nicotinic acid (niacin), pantothenic acid (vitamin B<sub>5</sub>), and biotin (vitamin B<sub>7</sub>) for growth, so these vitamins could be added to ''Pediococcus'' specific growth media. Other vitamins, such as riboflavin and pyridoxine, might stimulate growth for some strains of ''P. damnosus'' <refname="Wade_2018" />. * For information on mixed culture starters, see [[Mixed_Cultures#Starters_and_Other_Manufacturer_Tips|Mixed Culture Starters]]. ====Sulfur Dioxide====Sulfur dioxide (SO<sub>2</sub>) in the form of potassium metabisulfite is often used in wine to limit microbiological growth of yeast and bacteria, and oxidation. SO<sub>2</sub> maintains an equilibrium between molecular SO<sub>2</sub>Wine Microbiology, bisulfite, and sulfite ions. Practical Applications The molecular SO<sub>2</sub> portion interacts with cell walls because it has no charge, while the rest of the SO<sub>2</sub> has less of an impact on yeast and Proceduresbacteria cells (but can still have some inmpact on bacterial cells, depending on species). Kenneth CBelow a pH of 3.5, molecular SO<sub>2</sub> is higher, but above a pH of 3. Fugelsang5 the SO<sub>2</sub> binds more into bisulfite and sulfite ions, rendering it less effective against microbes. SO<sub>2</sub> can also become bound to other compounds such as acetaldehyde, pyruvic acid, anthocyanins, glucose, and glacturonic acid, Charles Gwhich also renders it less effective against microbes, although they can degrade and release molecular SO<sub>2</sub> as well <ref name="Wade_2018" />. ''Pediococcus'' and other lactic acid bacteria have a wide range of resistance to SO<sub>2</sub> depending on species and strain. One study by Edwardsand Jensen (1992) reported that ''P. parvulus'' was able to thrive in 20 mg/L of free SO<sub>2</sub> (0.39 mg/L molecular SO<sub>2</sub>), indicating that small amounts of SO<sub>2</sub> are not enough to inhibit ''Pediococcus''. Other studies have shown that different strains can be inhibited at concentrations between 100-256 mg/L total SO<sub>2</sub> <ref name="Wade_2018" />. ====Hop Resistance====''Pediococcus'' species and strains are generally resistant to hop compounds, and have been reported to grow in beer with at least 30 IBU <ref name="Geissler"></ref>, and together with ''Lactobacillus'' are reported to be responsible for ~70% of all beer spoilage incidents caused by microbes <ref name="Garcia-Garcia">[http://onlinelibrary.wiley.com/doi/10.1002/jib.397/abstract Pediococcus damnosus strains isolated from a brewery environment carry the horA gene. Jorge Hugo Garcia-Garcia, Luis Cástulo Damas-Buenrostro, Juan Carlos Cabada-Amaya, Myriam Elias-Santos, Benito Pereyra-Alférez. 2017. DOI: 10.1002/jib.397.]</ref>. It has been suggested by research that horizontal gene transfer (transfer of genetic material by means other than reproduction) allows ''Pediococcus'' species (and other LAB) to obtain the genes associated with resistance to hops (primarily multi-drug transporter "horA", along with "hitA", "horC", and "horB" <ref name="Garcia-Garcia" />). This has been thought to allow ''Pediococcus'' to adapt to living in beer <ref name="Garcia-Garcia" /><ref name="Snauwaert"></ref>. While able to grow in the presence of hops, the presence of hops still inhibits ''P. damnosus''. For example, one study found that in the presence of 15 IBU, lactic acid production was reduced by ~82%. Exposure to 15 IBU also increased diacetyl production by 350%, while 2,3-pentanedione (buttery, nutty, toasted, caramellic, diacetyl and acetoin notes <ref>[http://www.thegoodscentscompany.com/data/rw1003991.html "acetyl propionyl ". The Good Scents Company. Retrieved 01/18/2017.]</ref>) was decreased by 25%. Interestingly, exposure to 3% ABV and no hops reduced the production of diacetyl and 2,3-pentanedione by about 20%. The addition of vitamins, specifically thiamine (vitamin B1) and riboflavin (vitamin B2), increased the production of lactic acid in the presence of 15 IBU or no hops by about 15-30%. However, thiamine also increased diacetyl production by 100-125% and 2,3-pentadione production by 20-30% without the presence of hops. In the presence of 15 IBU, thiamine and/or riboflavin increased diacetyl production by about 26-36% and 2,3-pentadione by about 40-114% <ref>[http://onlinelibrary.wiley.com/doi/10.1002/jib.385/full The influence of thiamine and riboflavin on various spoilage microorganisms commonly found in beer. Barry Hucker, Melinda Christophersen, Frank Vriesekoop. 2017.]</ref>. Strains that are grown exposed to small amounts of iso-alpha acids can be adapted to survive higher amounts up to ~150 μg mL<sup>1</sup>. The implications of this in brewing mean that the bacteria can enter any stage of the process and remain in undetectable amounts until it adapts to higher IBU conditions and then potentially spoils beer <ref name="Garcia-Garcia" />. It was reported that ''Pedioccoccus pentosaceus'' can be inhibited by iso-alpha acids and beta acids (although beta acids are not soluble in beer or wort) and that the power of inhibition by these hop acids is greater in beer fermentation than it is on MRS media due to the lower pH of beer and the presence of ethanol. Hop acids, in general, lose their antimicrobial properties as the pH of their solution rises to around 5.5 <ref>[https://www.notulaebotanicae.ro/index.php/nbha/article/view/11687 Inhibitory Effects of Iso-α and β Hop Acids Against Pediococcus pentosaceus. Delia MICHIU, Frank DELVIGNE, Nicolas MABON, Mirela JIMBOREAN, Melinda FOGARASI, Mihaela MIHAI, Maria TOFANĂ, Philippe THONART. 2019.]</ref> ====Mixed Culture Influence==== See [[Lactic Acid]].
===Carbohydrate Metabolism===
==="Ropy" or "Sick" Beer===
[[File:Ropy example.jpg|thumb|300|Example of ropy beer brewed with The Yeast Bay Melange and dregs from Boon Mariage Parfait 2010. Photo is courtesy of Stuart Grant <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1148859311808948/ Conversation with Stuart Grant on MTF. 09/16/2015.]</ref>]]
[[File:EPS.gif|thumb|300|Exopolysaccharide pathway <ref name="ESP">[http://www.sciencedirect.com/science/article/pii/S0740002004000668 Glucose fermentation kinetics and exopolysaccharide production by ropy Pediococcus damnosus IOEB8801. Emilie Walling, Marguerite Dols-Lafargue, Aline Lonvaud-Funel. Food Microbiology Volume 22, Issue 1, January 2005, Pages 71–78.]</ref>]]
Some strains of ''P. damnosus'' (and other bacteria) can cause a beer (or wine) to go "ropy", also known as "sick" by [[lambic]] brewers (or more specifically as "the fat sickness, "; “la maladie de la graisse” in French <ref>[https://beerbybart.com/2011/04/03/true-lambic-jean-van-roy-cantillon-sick-beer/ True Lambic: Sick beers and the magic of Cantillon. Beer By Bart blog. Gail Ann Williams. 04/03/2011. Retrieved 04/23/2016.]</ref>). Reportedly, ropiness in beer that also has ''Brettanomyces'' (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) <ref name="ropy_time">[https://www.facebook.com/groups/MilkTheFunk/permalink/1132030550158491/ Poll on Milk The Funk regarding how long ropy beer has been observed. 08/20/2015.]</ref>. Some species of ''Pediococcus'' and other lactic acid bacteria have been reported to also be able to break down ropiness <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1670311836330357/?comment_id=1670331339661740&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Matt Humbard and Joe Idoni. Milk The Funk Facebook group. 04/29/2017.]</ref>. The viscosity of ropy beer has been reported to be higher at the bottom of wooden barrels than near the top, either due to sedimentation or perhaps more growth of ''Pediococcus'' near the bottom of wooden barrels due to yeast autolysis and/or less exposure to oxygen <ref name="Oevelen_1979" />. Despite the popularity of this talking point about ''Pediococcus'' in brewing, a lot of strains of ''Pediococcus'' used in brewing don't seem to produce ropiness, especially strains sourced from beer yeast labs. For example, Richard Preiss of [[Escarpment Laboratories]] reported only seeing ropiness from ''Pediococcus'' sourced from [[lambic]] <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2859721020722760/?comment_id=2859868767374652&comment_tracking=%7B%22tn%22%3A%22R%22%7D Richard Preiss. Milk The Funk Facebook group thread on the frequency of ''Pediococcus'' caused ropiness. 08/20/2019.]</ref>.
====Videos====* [[Filehttps:EPS//www.gif|thumb|300|Exopolysaccharide pathway <ref name="ESP">facebook.com/groups/MilkTheFunk/permalink/4547361381958707/ Highly viscous ropy beer video posted in MTF by Roi Funk Krispen.]* [httphttps://www.sciencedirectfacebook.com/sciencegroups/articleMilkTheFunk/piipermalink/S0740002004000668 Glucose fermentation kinetics 3478055812222608/ Post on MTF by Brandon Jones showing initial ropiness of a beer, and exopolysaccharide production by ropy Pediococcus damnosus IOEB8801then after aging the ropiness out for 8 weeks. Emilie Walling, Marguerite Dols-Lafargue, Aline Lonvaud-Funel]* [https://www. Food Microbiology Volume 22, Issue 1, January 2005, Pages 71–78facebook.]<com/groups/MilkTheFunk/permalink/1813022388725967/ref>]Other videos on MTF of ropy beer.]
===Bacteriocins===
Some strains of ''Pediococcus pentocaseus'' have been 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 a "class II" enteriocin that inhibits the growth of ''E. coli'' and ''Staphylococcus 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>. ''P. damnosus'' also produces an antimicrobial compound called pediocin PD-1, which can inhibit several bacteria spp including ''O. oeni'' <ref>[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>.
===Malolactic Fermentation===See the [[Cider#Microbes|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="Wade_2018" />. For more information on biogenic amines in beer in general, see [http://suigenerisbrewing.com/index.php/2019/01/22/biogenic-amines/ "Fact or Fiction – Biogenic Amines in Beer" by Dr. Bryan Heit]. Some strains of lactic acid bacteria, including ''Pediococcus'', can metabolize amino acids into biogenic amines, and potentially alsodegrade them <ref>[https:* //watermark.silverchair.com/0362-028x-60_7_831.pdf Tyramine Formation by Pediococcus spp. during Beer Fermentation. MARIA IZQUlERDO-PULIDO, JOSEP-MIQUEL CARCELLER-ROSA, ABEL MARINE-FONT, and M. CARMEN VIDAL-CAROU. 1996.]</ref><ref>[https://www.researchgate.net/publication/240429641_Effect_of_tyrosin_on_tyramin_formation_during_beer_fermentation Effect of tyrosin on tyramin formation during beer fermentation. Maria Izquierdo-Pulido, M. Carmen Vidal-Carou. 2000.]</ref>. The number of strains capable of producing biogenic amines appears to be very low. [Lactobacillus#Bacteriocins|https://link.springer.com/pdf%2F10.1007%2FBF01105812 Weiller and Radler (1976)] found that only one out 28 strains of ''P. cerevisiae'' (later reclassified to ''P. damnosus'' and ''LactobacillusP. pentosaceus'' bacteriocins) produced biogenic amines. [https://www.ncbi.nlm.nih.gov/pubmed/973463 Strickland et al. (2016)]found that out of multiple species of ''Pediococcus'', only one strain of ''P. inopinatus'' produced biogenic amines, and it only produced 3.3 mg/L of histamine. [https://www.sciencedirect.com/science/article/pii/S0168160511002893 García‐Ruiz et al. (2011)]reported that 9 out of 85 strains of ''P. parvulus'' and ''P. pentosaceus'' were able to degrade some biogenic amines (histamine, tyrosine, and putrescine) in culture media, but were unable to do so in wine, indicating that any degradation of biogenic amines in wine that might occur is not likely due to lactic acid bacteria, but due to some other cause <ref name="Wade_2018" />.
De Roos et al (2024) found the ''P. damnosus'' in two samples of lambic had the genetic capability to produce histamine. The total biogenic amine content of the lambic was at levels below that which has been deemed safe by European regulatory bodies <ref name===Mixed Culture Influence==="Roosa_2024"/>.
See also:* [[Lactic AcidSpontaneous_Fermentation#Biogenic_Amines|Biogenic amines in spontaneously fermented beer.]]* [[Brettanomyces#Biogenic_Amines|Biogenic amine production by ''Brettanomyces''.]]* [[Wine#Biogenic_Amines|Biogenic amines in wine.]]* [http://www.horscategoriebrewing.com/2019/01/spontaneous-fermentation-and-biogenic.html "Spontaneous fermentation and biogenic amines" by Dr. Dave Janssen; review of several studies that looked at the levels of biogenic amines in different beers and their production, and their potential flavor contribution.]* [http://suigenerisbrewing.com/index.php/2019/01/22/biogenic-amines/ "Fact or Fiction – Biogenic Amines in Beer" by Dr. Bryan Heit; an analysis of biogenic amines in spontaneously fermented beer and 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 biogenic amines.]
===Hop ResistanceOther Metabolites===''PediococcusP. claussenii'' tends to produce a smaller amount of acetic acid than lactic acid in about a 1:3 ratio. ''P. damnosus'' species and strains are generally resistant tends to hop compounds, produce only lactic acid and have been reported to grow in beer with at least 30 IBU 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, Rudi F. Vogel. 2015.]</ref>, and together with ''Lactobacillus'' are reported although some strains have been found to be responsible for ~70% produce small amounts of acetic acid of all around 100-300 ppm. This level is slightly below and above flavor thresholds in lager beer spoilage incidents caused by microbes (but could be additive with other organisms) <ref name="Garcia-Garcia">[http://onlinelibrary.wiley.com/doi/10.1002/jibj.2050-0416.3972010.tb00393.x/abstract Pediococcus damnosus strains isolated Isolation, Identification, and Characterisation of Beer-Spoilage Lactic Acid Bacteria from Microbrewed Beer from a brewery environment carry the horA geneVictoria, Australia. Garry Menz, Christian Andrighetto, Angiolella Lombardi, Viviana Corich, Peter Aldred, Frank Vriesekoop. Jorge Hugo Garcia-Garcia2010.]</ref>, Luis Cástulo Damasbut significantly less than the total acetic acid often found in gueuze (around 700-Buenrostro, Juan Carlos Cabada2200 ppm <ref>[http://www.horscategoriebrewing.com/2016/07/duivelsbier-Amaya, Myriam Eliasof-Santoshalle.html Jansen, Benito Pereyra-AlférezDave. 2017Hors Category Blog. DOI: 10"Duivelsbier of Halle".1002 07/30/jib2016.397 Retrieved 01/31/2018.]</ref>. It has been suggested by research that horizontal gene transfer (transfer of genetic material by means other than reproduction) allows ''Pediococcus'' species and Flanders reds (300-2300 ppm <ref>[http://www.sciencedirect.com/science/article/pii/S0168160515301896 Microbial diversity and other LAB) to obtain the genes associated with resistance to hops (primarily multimetabolite composition of Belgian red-drug transporter "horA"brown acidic ales. Isabel Snauwaert, Sanne P. Roels, Filip Van Nieuwerburg, along with "hitA"Anita Van Landschoot, "horC"Luc De Vuyst, and "horB" Peter Vandamme. 2015.]</ref name="Garcia-Garcia" />). This has been thought to allow ''Pediococcus'' to adapt to living in beer <ref name="Garciaalso carries the decarboxylase enzyme (PAD) which converts hydroxycinnamic acid (ferulic acid) into phenols (4-Garcia" />vinyl guaiacol) <ref name="Snauwaertlentz_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 able ''Pediococcus'' has been linked to grow in the presence creation of hops, acrolein via the presence metabolism of hops still inhibits glycerol, evidence supports that this is very rare in ''P. damnosusPediococcus''. For example, one study found that in the presence of 15 IBU, lactic acid production was reduced by ~82%species. Exposure to 15 IBU also increased diacetyl production by 350%, while 2,3-pentanedione (buttery, nutty, toastedIn wine, caramellic, diacetyl acrolein reacts with anthocyanins and acetoin notes <ref>[http://www.thegoodscentscompany.com/data/rw1003991.html "acetyl propionyl "other phenols to produce an intense bitterness. The Good Scents CompanyAcrolein production in wine has been linked to some strains of ''Lactobacillus''. Retrieved 01/18/2017.]</ref>) was decreased by 25%. Interestingly, exposure Some strains of ''Pediococcus'' have been found to 3% ABV metabolize gylcerol in beer and no hops reduced the production of diacetyl wine under aerobic and 2,3semi-pentanedione by about 20%. The addition of vitamins, specifically thiamine (vitamin B1) and riboflavin (vitamin B2)aerobic environments, increased but the production metabolism of lactic acid glycerol in the presence of 15 IBU or no hops by about 15-30%. However, thiamine also increased diacetyl oxygen results in the production by 100-125% and 2of lactic acid,3-pentadione production by 20-30% without the presence of hops. In the presence of 15 IBUacetic acid, thiamine and/or riboflavin increased diacetyl production by about 26-36% , and 2,3-pentadione by about 40-114% <ref>[http://onlinelibrary.wiley.com/doi/10.1002/jib.385/full The influence of thiamine and riboflavin on various spoilage microorganisms commonly found in beer. Barry Hucker, Melinda Christophersenbutanediol, Frank Vriesekoop. 2017.]</ref>. Strains that are grown exposed to small amounts of iso-alpha acids can be adapted to survive higher amounts up to ~150 μg mL<sup>1</sup>. The implications of this in brewing mean that the bacteria can enter any stage of the process and remain in undetectable amounts until it adapts to higher IBU conditions and then potentially spoils beer not acrolein <ref name="Garcia-GarciaWade_2018" />.
==Storage==