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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. 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]].

See ''[[Lactobacillus]]'', ''[[Brettanomyces]]'', ''[[Saccharomyces]]'', [[Mixed Cultures]], [[Kveik#Commercial_Availability|Kveik]], and [[Nonconventional Yeasts and Bacteria]] charts for other commercially available cultures.

''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://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''.]

| [[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.

| [[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'''.

====[[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]]).

===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 O₂.JPG The presence of CO₂ 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 B₅), and biotin (vitamin B₇) 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 (SO₂) in the form of potassium metabisulfite is often used in wine to limit microbiological growth of yeast and bacteria, and oxidation. SO₂ maintains an equilibrium between molecular SO₂Wine Microbiology, bisulfite, and sulfite ions. Practical Applications The molecular SO₂ portion interacts with cell walls because it has no charge, while the rest of the SO₂ 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 SO₂ is higher, but above a pH of 3. Fugelsang5 the SO₂ binds more into bisulfite and sulfite ions, rendering it less effective against microbes. SO₂ 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 SO₂ as well <ref name="Wade_2018" />.  ''Pediococcus'' and other lactic acid bacteria have a wide range of resistance to SO₂ 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 SO₂ (0.39 mg/L molecular SO₂), indicating that small amounts of SO₂ are not enough to inhibit ''Pediococcus''. Other studies have shown that different strains can be inhibited at concentrations between 100-256 mg/L total SO₂ <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 mL¹. 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]].

About 90% of sugar metabolized by ====VBNC====''PediococcusP. damnosus'' produces lactic acid. It does has been found to be able to enter a so by homolactic fermentation producing primarily lactic acid -called "viable but nonculturable (same EMP pathway as [[Lactobacillus#Types_of_Metabolism|''Lactobacillus'' homolactic fermentation]]VBNC)state" where cells are not culturable by routine means, although some species/strains can convert glycerol to lactic acid, acetic acid, acetoin, but are still alive and CO2 under aerobic recoverable when stress conditions (''Pare removed. damnosus'' is not This can lead to problems identifying these microorganisms in this category) <ref>potentially spoiled products. See [https://bookswww.googlesciencedirect.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 science/article/pii/S002364382101776X Zhenbo Xu et .al (2021)]</ref>. However, all species in the for potential resuscitation strategies for ''PediococcusP. damnosus'' genus are considered obligatory homofermentative because of the pathways that they use <ref>[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>.

===Malolactic Fermentation===See also:See the * [[CiderQuality_Assurance#MicrobesViable_But_Nonculturable|CiderQuality Assurance]] page.

''P. damnosus'' can ferment glucose, sucrose, and galactose. Some strains of ''P. damnosus'' can ferment maltose and sucrose <ref name="ucdavis"></ref>. The disaccharide trehalose is the preferred carbon source for Pediococci <ref name="Geissler"></ref>. While simple sugars are the primary food source for ''Pediococcus'', many strains of ''P. damnosus'' have been observed to produce varying degrees of both alpha and beta-glucosidase enzymes. Alpha-glucosidase enzymes have the ability to break down higher chain sugars, including dextrins, starches, and glucans (possibly even the glucans that are produced by ''P. damnosus'' that result in ropy beer). The types of beta-glucosidase enzymes produced by ''P. damnosus'' are thought to perhaps play a role in breaking down monoglycosidic bonds (see [[Glycosides]]), but cannot break down the more complex diglycosidic bonds which are needed to break down many glycosides that would release flavor and aroma compoundsFile:Pedio sugars. Compared to the microbe JPG|thumb|''Oenococcus oeni'' which is often used in wine and cider fermentation (malolactic fermentation) and has been shown to have more impactful beta-glucosidase activity, ''P. damnosusPediococcus'' is thought to be less impactful fermentables based on glycosides. Unlike ''O. oeni'' which decreases its enzymatic activity in low pH conditions, enzymatic activity of ''P. damnosus'' is very stable at a pH of 3-4. Very low concentrations of glucose or fructose (1 g/l) inhibit this enzymatic activity in ''P. damnosus''. The presence of alcohol inhibits the alpha-glucosidase activity in most strains, which might contribute to longer lasting ropiness in beer. The optimal temperature for enzymatic activity in ''P. damnosus'' is between 35-40°C (95-104°F) <ref>species; table from [httphttps://onlinelibrarywww.wileyspringer.com/doius/10.1111book/j.1365-2672.2005.02707.x/full Screening of Lactobacillus spp9780387333410 "Wine Microbiology. Practical Applications and Pediococcus sppProcedures. for glycosidase activities that are important in oenology. A", Kenneth C. GrimaldiFugelsang, ECharles G. BartowskyEdwards, V. Jiranek. 2005. DOI: 10.1111/j.1365-2672.2005.02707.x2007.]</ref>.]]

===Growth and Environment===''P. damnosus'' is sensitive to temperature can ferment glucose, sucrose, and pHfructose. It is unable to grow at a pH Some strains of 8 or higher or at 35°C. The optimal growth occurs at 22°C and 5.5 pH. ''P. damnosus'' is sensitive to environments that contain NaClcan ferment maltose, sucrose, and will not grow with concentrations of 4% NaCl galactose <ref name="ucdavis"></ref><ref name="Oevelen_1979" />. The disaccharide trehalose is the preferred carbon source for pediococci <ref name="Geissler"></ref>. Most While simple sugars are the primary food source for ''Pediococcus'', many strains of ''P. clausseniidamnosus'' can grow have been observed to produce varying degrees of both alpha and beta-glucosidase enzymes. Alpha-glucosidase enzymes have the ability to break down higher chain sugars, including dextrins, starches, and glucans (possibly even the glucans that are produced by ''P. damnosus'' that result in ropy beer). About half of the strains tested The types of beta-glucosidase enzymes produced by ''P. damnosus'' can grow are thought to perhaps play a role in beerbreaking down monoglycosidic bonds (see [[Glycosides]]), but cannot break down the more complex diglycosidic bonds which are needed to break down many glycosides that would release flavor and aroma compounds. Compared to the microbe ''Oenococcus oeni'' which is often used in wine and none cider fermentation (malolactic fermentation) and has been shown to have more impactful beta-glucosidase activity, ''P. damnosus'' is thought to be less impactful on glycosides. Unlike ''O. oeni'' which decreases its enzymatic activity in low pH conditions, enzymatic activity of ''P. damnosus'' is very few strains stable at a pH of 3-4. Very low concentrations of glucose or fructose (1 g/l) inhibit this enzymatic activity in ''P. acidilacticidamnosus''. The presence of alcohol inhibits the alpha-glucosidase activity in most strains, which might contribute to longer lasting ropiness in beer. The optimal temperature for enzymatic activity in ''P. parvulusdamnosus''is between 35-40°C (95-104°F) <ref>[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2005.02707.x/full Screening of Lactobacillus spp. and Pediococcus spp. for glycosidase activities that are important in oenology. A. Grimaldi, E. Bartowsky, and V. Jiranek. 2005. DOI: 10.1111/j.1365-2672.2005.02707.x.]</ref>. Some strains of ''P. pentosaceusdamnosus'' found in lambic have been found to grow contain the genetic capability of breaking down ferulic acid into 4-vinylphenol, which can assist in finished beerethyl phenol production later on by ''[[Brettanomyces]]'' <ref name="Roosa_2024">De Roos, J., Vermotea, L., Cnockaertb, M., Vandammeb, P., Weckxa, S., & De Vuysta, L. WOODEN BARRELS HELP TO STEER THE LAMBIC BEER FERMENTATION AND MATURATION PROCESS.</ref>. ===Lactic Acid Production===[[File:Pedio EMP Pathway.jpg|thumb|200px|right|[https://onlinelibrary.wiley.com/doi/full/10.1111/ajgw.12366 Homofermentative Embden–Meyerhof–Parnas (EMP) pathway for the production of lactic acid, acetoin, diacetyl and 2,3‐butanediol and acetic acid production from citrate metabolism. Image by Wade et al (2018). ]]]

One study showed that optimal growth About 90% of sugar metabolized by ''Pediococcus'' produces both L- and D-lactic acid <ref name="Wade_2018" />. was observed in It does so by homolactic fermentation producing primarily lactic acid (same EMP pathway as [[http://www.neogen.com/Acumedia/pdf/ProdInfo/7406_PI.pdf MRS mediaLactobacillus#Types_of_Metabolism|''Lactobacillus'' homolactic fermentation]] after ~84 hours with an initial pH of 6.7), and a final pH of 4.14although some species/strains can convert glycerol to lactic acid, which occurred naturally from fermentation. The addition of bacteriological peptoneacetic acid, MnSO4acetoin, and Tween 80 also increased activity. Maximum cell densities of CO2 under aerobic conditions (''P. damnosus'' are around 4.3 billion cells/mL is not in MRS media starting at a pH of 5.5 this category) <ref>[https://wwwbooks.facebookgoogle.com/groups/MilkTheFunk/permalink/1347683325259878/books?comment_idid=1b1CAgAAQBAJ&pg=RA2-PA1&lpg=RA2-PA1&dq=pediococcus+damnosus+homolactic&source=bl&ots=myI2alVB78&sig=cG-yWB4GuABQFEtqD2CAyKmU0TE&hl=en&sa=1349386438422900X&reply_comment_idved=0CEAQ6AEwBGoVChMI66C5593-xgIVCVKICh3Pcg7c#v=1350340544994156onepage&comment_trackingq=pediococcus%7B20damnosus%22tn%22%3A%22R%22%7D Conversation with Richard Preiss on MTF regarding 20homolactic&f=false Encyclopedia of Food Microbiology. Pediococcus cell density. 07/19/2016Carl A. Batt. Academic Press, Sep 28, 1999 .]</ref>. Some strains of ''P. pentosaceus'' can ferment five-chain sugars such as xylose to produce acetic acid and lactic acid. Some strains of ''P. halophilus'' (now reclassified as ''Tetragenococcus halophilis'') can 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 temperature. However, all species in the ''Pediococcus'' genus are considered obligatory homofermentative because of the pathways that they use <ref name="Nel">[http://wwwaem.ncbiasm.nlm.nih.govorg/content/81/pubmed20/11851822 Growth optimization 7233.full A Genomic View of Pediococcus damnosus NCFB 1832 Lactobacilli and the influence of pH pediococci Demonstrates that Phylogeny Matches Ecology and nutrients on the production of pediocin PD-1Physiology. Nel HA Jinshui Zheng, Bauer RLifang Ruan, Vandamme EJ, Dicks LMMing Sun and Michael Gänzle. 2001 2015.]</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 name="Wade_2018" /><ref>[https://wwwaem.redditasm.comorg/rcontent/Homebrewing53/comments6/3qp7b7/advanced_brewers_round_table_neva_parker_white/cwh7iqq Neva Parker1257.short Citrate Metabolism by Pediococcus halophilus. Chiyuki Kanbe, Reddit threadKinji Uchida. 10/29/20151987.]</ref>.

Although more experiments are probably needed, agitation is believed to be an important factor for any species ===Diacetyl and Acetoin===''P. damnosus'' can produce high amounts of microbe (yeast diacetyl and bacteria)acetoin during lactic acid production <ref>[http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2672.2000.00956.x/pdf Identification of pediococci by ribotyping. Gentle stirring on a stir plate or orbital shakerR. Satokari, or frequent gentle manual agitation leads to faster growth T. Mattila-Sandholm and a higher number of organismsM. Agitation keeps the microbes in solutionL. It also maximizes the microbes' access to nutrients and disperses waste evenlySuihko. In a non-agitated starterJournal of Applied Microbiology 2000, the microbes are limited to the diffusion rate of nutrients88, leading to a slower and more stressful growth 260–265.]</ref><ref>[httpshttp://wwwmmbr.facebookasm.comorg/groupscontent/MilkTheFunk77/permalink2/1168024059892473/?comment_id=1174865305875015&reply_comment_id=1176092372418975&total_comments=1&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with Bryan 157.full The Microbiology of Sui Generis Blog about starters Malting and agitationBrewing. 11/09/2015Nicholas A. Bokulicha, and Charles W. Bamforth. June 2013.]</ref>. Although Diacetyl is the 'buttery'Pediococcus'' are aroma and flavor found in beer (generally considered facultative anaerobes not favorable) and oxygen usually does not negatively affect their growth, some strains may show less growth in the presence of oxygen wine (favorable in amounts between 1-4 mg/L). While other microbes found in beer and are considered anaerophilic, meaning that the presence of oxygen inhibits their growth wine fermentation (and therefore their acid productionnamely ''Saccharomyces cerevisiae'') but they can still grow in the presence of O2. The presence of CO2 has a positive effect on also produce diacetyl, ''Pediococcus'' and other lactic acid production bacteria are known to be able to produce much higher amounts <ref name="NAKAGAWAWade_2018"></ref> . Therefore, it is generally best practice to seal the starter with an airlock.

====Starter Information====General starter information In lactic acid bacteria, diacetyl can be the byproduct of both homofermentative metabolism of sugars as well as the metabolism of citric acid, and it is a way for commercial ''Pediococcus'' cultures is limitedthe cells to regenerate NADP⁺. In addition either of these two pathways, extra pyruvate is turned into alpha-acetolactate which then undergoes an oxidative decarboxylation reaction to the various [[Pediococcus#Manufacturer_Tips|starter suggestions produce diacetyl. Diacetyl is often reduced by various labs]] regarding their individual culturesyeast to acetoin and/or 2,3-butanediol, Jeff Mello which have a higher threshold and less 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 an impact on the finished beer/wine <ref name="mello_starterWade_2018"></ref>. This same formula might benefit other ''Pediococcus'' starters as well. The CaCO3 serves as a buffering agent that keeps In mixed fermentation sour beer, the starter pH from getting too low too fastbreakdown of diacetyl into acetoin and 2, and 3-butanediol is similar often thought to the concept of buffered growth media for be carried out by ''LactobacillusBrettanomyces'' (see [[Lactobacillus#Samuel_Aeschlimann.27s_Starter_Procedures|in a similar way to ''LactobacillusSaccharomyces'' Starter]])species, but this has not been investigated that we are aware of. Starters It has been reported that diacetyl reduction is faster at a lower pH of ''Paround 3. damnosus'' cultures could require around 84 hours 5, which is a typical pH range for optimal growthsour beer and might be one of the contributing factors to a lack of anecdotal reports of diacetyl in sour beer <ref>[https://onlinelibrary.wiley.com/doi/full/10.1002/jib.381 Michel, M., however this time requirement hasn't been looked at in wort starters Meier‐Dörnberg, T., Jacob, F., Methner, F. ‐J., Wagner, R. S., and Hutzler, M. (only MRS media2016) Review: Pure non‐Saccharomyces starter cultures for beer fermentation with a focus on secondary metabolites and practical applications. J. Inst. Brew., 122: 569– 587. doi: 10.1002/jib.381.]</ref><ref name="Nelkrogerus_2013">[https://www.researchgate.net/publication/259331290_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://doi.org/10.1002/jib.84.]</ref>.

* Several variables the affect diacetyl and acetoin production have been identified. First of all, some strains of ''Pediococcus'' species produce diacetyl, and others do not. During malolactic fermentation (conversion of citric acid to lactic acid), the temperature at which MLF is conducted can influence whether or not diacetyl is produced. For information example, two studies reported that more diacetyl and acetoin were produced during the MLF in wine at 18°C compared at 25°C. 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 diacetyl down to acetoin and 2,3-butanediol (extended time exposed to active yeast or on mixed culture starterslees can reduce diacetyl in wine and probably also beer). If SO₂ is used, it can bind to diacetyl in a form that cannot be tasted, see [[Mixed_Cultures#Starters_and_Other_Manufacturer_Tips|Mixed Culture Starters]]although the SO₂ can become unbound and release the diacetyl again. An increase in citric acid can also lead to more diacetyl under semi-aerobic conditions but not anaerobic conditions. The presence of glucose has also been associated with higher levels of diacetyl production in wine <ref name="Wade_2018" />.

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>.

This "ropiness" is caused by production of exopolysaccharides (EPS) in the form of β[https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-37-glucans 0034 Oevelen and Verachtert (beta glucans1979) by some strains ] demonstrated that ''PediococcusBrettanommyces bruxllensis'' and some other lactic acid bacteria species. A small amount of β-glucan is adequate enough to affect reduces the visible viscosity of beer or wine. The gene known as "dps" has been identified with the production of β-glucan/EPS in ropiness produced by ''P. damnosusPediococcus'', and the gene "gtf" in but that at least one strain of ''P. clausseniiSaccharomyces cerevisiae'' does not <ref name="SnauwaertOevelen_1979"></ref>. Not all The scientists tested two strains of ''B. bruxellensis'', and when either one of these strains were co-pitched with a strain of ''P. damnosus'' (formerly called ''P. cerevisiae''), at two weeks there was the same level of viscosity as when the ''P. damnosus'' express strain was pitched by itself, but at 4 weeks the viscosity was greatly reduced (although the viscosity was still higher than when there was no ''Pediococcus'' present). When they co-pitched a strain of ''Saccharomyces cerevisiae'' with the ''Pediococcus'', the geneviscosity remained high at 4 weeks, and only ones demonstrating that do will cause a beer this strain of ''S. cerervisiae'' was not able to go ropy. Although reduce the viscosity of the ropiness (it is not needed to survive in beer, EPS production is probably has importance in biofilm production <ref>[http://catknown if this strain of ''S.inistcerevisiae'' was diastatic or not).fr/?aModele=afficheN&cpsidt=23890699 Ethanol tolerance The scientists also attempted to stagger the pitch of lactic acid bacteria''Brettanomyces'', including relevance pitching it two weeks after the ''Pediococcus''. This resulted in very low growth of the exopolysaccharide gene gtf. Pittet V, Morrow K, Ziola B. 2011.]</ref>, and ''PediococciBrettanomyces'' and no reduction in viscosity due to that are ropy have been found limited growth. The limited growth was attributed to be more acid, alcohol, and SO2 tolerant than other the low pH that the ''PediococciBrettanomyces''yeast was exposed to at inoculation time. The thickness ''Brettanomyces'' was able to reduce the viscosity when the scientists add another 10 g/L of glucose, and buffered the ropiness pH to 4. The researchers also found that when ropy media was exposed to air, it immediately disappeared. However, exposing ropy beer to air is increased not an acceptable method for dealing with the presence of malic ropiness due to oxidation and acetic acid production in sour beer when it is exposed to oxygen <ref name="ESPOevelen_1979"></ref>. The exact enzymatic activity for how ''Brettanomyces'' (or other microorganisms) break down EPS from ''Pediococcus'' is not well characterized, but it could be due to alpha-glucosidase activity in those yeasts (see [[Brettanomyces#Carbohydrate_Metabolism_and_Fermentation_Temperature|''Brettanomyces'' metabolism]] and [[Pediococcus#Carbohydrate_Metabolism|Carbohydrate Metabolism]] above).

One study showed that This "ropiness" is caused by production of exopolysaccharides (EPS) in the production form of β-glucan coincided with the end of the growth phase of glucans (beta glucans) by some strains ''Pediococcus''and some other lactic acid bacteria species. While small amounts Ropiness also contains 4-15% proteins and nucleic acid in the form of RNA <ref name="Oevelen_1979" />. The β-glucan were produced during growthglucans are made up of beta 1, 3 linkages and beta 1, after 2 days branches composed of growth, β-glucan production increased as growth slowedsingle units <ref name="Wade_2018" />. A small amount (20-30 mg/L <ref name="Wade_2018" />) of β-glucan production stopped when growth stoppedis adequate enough to affect the visible viscosity of beer or wine. This study showed that The gene known as "dps" has been identified with the production of β-glucan production is linked to /EPS in ''PediococcousP. damnosus'' growth, producing more towards and the end of growthgene "gtf" in ''P. claussenii'' <ref name="Snauwaert"></ref>. This would explain why beer containing Not all strains of ''PediococcusP. damnosus'' often goes express the gene, and only ones that do will cause a beer to go ropy shortly after naturally carbonating in the bottle. This study found that other variables were Although it is not factors needed to survive in the beer, EPS production is probably has importance in biofilm production <ref>[http://cat.inist.fr/?aModele=afficheN&cpsidt=23890699 Ethanol tolerance of β-glucanlactic acid bacteria, such differing levels including relevance of alcohol (although alcohol interacts with the β-glucan in a way that makes the viscosity seem thicker)exopolysaccharide gene gtf. Pittet V, Morrow K, Ziola B. The study also found 2011.]</ref>, and pediococci that the lack of agitation increased the β-glucan production (wine makers will often agitate or aerate are ropy wine have been found to cure the wine from ropiness). A higher initial pH encourages higher growth (5.5+)be more acid, which increases β-glucan production. A lower initial pH (3.5)alcohol, decreases growth and β-glucan productionSO2 tolerant than other pediococci. A higher concentration The thickness of glucose the ropiness is increased growth and β-glucan productionwith the presence of malic acid <ref name="ESP"></ref>. Glucose is needed for β-glucan productionWhile strains of ''P. damnosus'' and ''P. While fructose alone is mostly insufficient to produce parvulus'' are the ''Pediococcus'' species most associated with ropiness, a combination some strains of glucose and fructose was slightly more efficient than glucose alone ''P. pentosaceus'' have also been found to produce EPS <ref name="ESPWade_2018"></ref>.

Temperature and nitrogen levels also affect how much EPS is produced. One study found showed that at 12°C both the production of β-glucan coincided with the end of the growth and EPS production was much slower than at 25°Cphase of ''Pediococcus''. After 29 While small amounts of β-glucan were produced during growth, after 2 days in agar mediaof growth, the EPS in the 12°C samples tended β-glucan production increased as growth slowed. β-glucan production stopped when growth stopped. This study showed that β-glucan production is linked to reach or slightly exceed ''Pediococcous'' growth, producing more towards the levels end of growth. This study found that other variables were not factors in the 25°C samplesproduction of β-glucan, which developed equivilant such as differing levels of EPS alcohol (or slightly lessalthough alcohol interacts with the β-glucan in a way that makes the viscosity seem thicker) within 7-13 days. Nitrogen levels The study also play a significant role, according to this study, particularly at lower fermentation temperatures. At 12°C, nitrogen was more important for found that the formation lack of EPS than glucose agitation increased the β-glucan production (although glucose was found wine makers will often agitate or aerate ropy wine to be cure the most important factor in EPS development overallwine from ropiness). A higher initial pH encourages higher growth (5.5+), which is in agreement with the previously sited study)increases β-glucan production. At 25°C nitrogen levels played a significant role in producing EPSA lower initial pH (3.5), however less so than glucose levelsdecreases growth and β-glucan production. In general though, A higher availability of nitrogen complimented higher levels concentration of glucose increased growth and β-glucan production. Glucose is needed for β-glucan production. While fructose alone is mostly insufficient to produce ropiness, a combination of glucose and fructose was slightly more EPS (and faster/higher cell growth) efficient than glucose alone <refname="ESP">[https:<//www.sciencedirect.com/science/article/pii/S0168160503000606 Exopolysaccharide production by Pediococcus damnosus 2.6 in a semidefined medium under different growth conditionsref>. Maite DueñasThe introduction of malic acid, Arantza Munduateglucose, Aidé Pereafructose, Ana Irastorza. 2003.]<and/ref>or nitrogen from things like fruit that is added to sour beer or even sugar added for natural carbonation can trigger ''Pediococcus'' growth and EPS production.

The presence of beta-glucans from barley have been observed to extend both the growth Temperature and the viability of ''Lactobacillus'' species in probiotics, indicating that ropiness might be a stress response <ref>[http://www.mdpi.com/1422-0067/15/2/3025/htm Barley β-Glucans-Containing Food Enhances Probiotic Performances of Beneficial Bacteria. Mattia P. Arena, Graziano Caggianiello, Daniela Fiocco, Pasquale Russo, Michele Torelli, Giuseppe Spano, and Vittorio Capozzi. 2014.]</ref><ref>[http://www.mdpi.com/1422-0067/13/5/6026/htm Beta-Glucans Improve Growth, Viability and Colonization of Probiotic Microorganisms. Pasquale Russo, Paloma López, Vittorio Capozzi, Pilar Fernández de Palencia, María Teresa Dueñas, Giuseppe Spano, and Daniela Fiocco. 2012.]</ref>nitrogen levels also affect how much EPS is produced. One study looked at this effect in beta-glucans produced by ''Pediococcus parvulus'' and found that ''L. plantarum'' had a longer viability in a fermented medium with no additional food source when that medium was first fermented with ''P. parvulus'' at 12°C both growth and EPS production was producedmuch slower than at 25°C. The ''L. plantarum'' strain that was tested did not ferment After 29 days in agar media, the beta-glucans. This suggests that there is an interspecies simbiotic relationship between lactic acid bacteria that produce EPS and those that don'tin the 12°C samples tended to reach or slightly exceed the levels in the 25°C samples, and when which developed equivilant levels of EPS is produced (betaor slightly less) within 7-glucans are present) the bacteria survive longer13 days. The Nitrogen levels also play a significant role, according to this study also observed that , particularly at lower fermentation temperatures. At 12°C, nitrogen was more important for the formation of EPS than glucose (although glucose was produced found to be the most important factor in an oat based wort and a rice based wortEPS development overall, while no EPS was produced which is in agreement with the previously cited study). At 25°C nitrogen levels played a barley based wortsignificant role in producing EPS, however less so than glucose levels. In general though, suggesting that different food sources influence whether or not higher availability of nitrogen complimented higher levels of glucose to produce more EPS is produced (and faster/higher cell growth) <ref>[httphttps://www.mdpisciencedirect.com/1422-0067/18science/7article/1588pii/htm In Situ β-Glucan Fortification of Cereal-Based Matrices S0168160503000606 Exopolysaccharide production by Pediococcus parvulusdamnosus 2.6 in a semidefined medium under different growth conditions. Adrián Pérez-RamosMaite Dueñas, María Luz MohedanoArantza Munduate, Paloma LópezAidé Perea, Giuseppe Spano, Daniela Fiocco, Pasquale Russo, and Vittorio CapozziAna Irastorza. 20172003.]</ref>. No studies have Stress in the environment such as ethanol and SO₂ has also been done on shown to induce EPS production, and a lack of available glucose has been associated with eliminating the growth or survivability production of lactic acid bacteria EPS (e.g. malolactic fermentation by ''Pediococcus'' in wine tends not to produce EPS, perhaps due to the present lack of EPS glucose in beer, which is a more harsh the environment than what was tested in these studies) <ref name="Wade_2018" />.

It has The presence of beta-glucans from barley have been observed that to extend both the growth and the viability of ''Lactobacillus'' species can produce EPS (''Lactococcus lactis''in probiotics, indicating that ropiness might be a stress response <ref>[http://www.mdpi.com/1422-0067/15/2/3025/htm Barley β-Glucans-Containing Food Enhances Probiotic Performances of Beneficial Bacteria. Mattia P. Arena, Graziano Caggianiello, Daniela Fiocco, Pasquale Russo, ''Lactobacillus delbrueckii''Michele Torelli, ''Lactobacillus casei''Giuseppe Spano, and ''Lactobacillus helveticus'') Vittorio Capozzi. 2014.]</ref name="ESP"><ref>[http://www.mdpi.com/1422-0067/13/5/6026/htm Beta-Glucans Improve Growth, Viability and Colonization of Probiotic Microorganisms. Pasquale Russo, Paloma López, Vittorio Capozzi, Pilar Fernández de Palencia, María Teresa Dueñas, Giuseppe Spano, and Daniela Fiocco. 2012.]</ref>. Some species of yeast can also produce EPS, including One study looked at this effect in beta-glucans produced by ''Pediococcus parvulus'Candida'and found that ', 'L. plantarum'Cryptococcus'had a longer viability in a fermented medium with no additional food source when that medium was first fermented with ', 'P. parvulus'Debaryomyces'and EPS was produced. The ', 'L. plantarum'Lipomyces'strain that was tested did not ferment the beta-glucans. This suggests that there is an interspecies simbiotic relationship between lactic acid bacteria that produce EPS and those that don't, ''Pichia'' and when EPS is produced (beta-glucans are present) the bacteria survive longer. The study also observed that more EPS was produced in an oat based wort and a rice based wort, while no EPS was produced in a barley based wort, suggesting that different food sources influence whether or not EPS is produced <ref>[httpshttp://www.facebookmdpi.com/groups1422-0067/MilkTheFunk18/permalink7/24659809367634391588/ Zach taggarthtm In Situ β-Glucan Fortification of Cereal-Based Matrices by Pediococcus parvulus. Milk Adrián Pérez-Ramos, María Luz Mohedano, Paloma López, Giuseppe Spano, Daniela Fiocco, Pasquale Russo, and Vittorio Capozzi. 2017.]</ref>. Pittet et al. (2011) found that the presence of the Funk Facebook group post on EPS from yeastgenes in lactic acid bacteria did not correspond with the ability to survive beer-level ethanol levels or higher, which led to the hypothesis that perhaps EPS provides LAB a way to assist in the formation of [[Quality_Assurance#Biofilms|biofilm]], although this has yet to be demonstrated scientifically <ref>[https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-2011-0124-01 Ethanol Tolerance of Lactic Acid Bacteria, Including Relevance of the Exopolysaccharide Gene Gtf. Vanessa Pittet and Kendra Morrow and Barry Ziola. 2011. 01DOI: https://doi.org/1610.1094/2019ASBCJ-2011-0124-01.]</ref>. Along these same lines, [https://www.academia.edu/27927065/Lysozyme_resistance_of_the_ropy_strain_Pediococcus_parvulus_IOEB_8801_is_correlated_with_beta_glucan_accumulation_around_the_cell Coulon et al. (2012)] reported that an EPS producing strain of ''PseudozymaPediococcus parvulus''was more resistant to the antimicrobial enzyme [https://en.wikipedia.org/wiki/Lysozyme lysozyme], which is often added to wine to kill lactic acid bacteria. The beta-glucan EPS formed a "coat" around the cells of the bacteria, thus protecting it from the lysozyme enzyme. When a beta-glucanase enzyme was added to break down the EPS produced by the bacteria, ''Rhodotorula'' the beta-glucan "coat" disappeared from the cell walls and the lysozyme was once again effective at killing this strain of ''SporobolomycesPediococcus'' <ref name="Gientka_2015">[https://www.researchgateacademia.netedu/publication27927065/283498621_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 biosynthesisLysozyme_resistance_of_the_ropy_strain_Pediococcus_parvulus_IOEB_8801_is_correlated_with_beta_glucan_accumulation_around_the_cell Coulon, chemical composition and functional properties Joana et al. “Lysozyme Resistance of the Ropy Strain Pediococcus Parvulus IOEB 8801 Is Correlated with Beta- reviewGlucan Accumulation around the Cell.” International Journal of Food Microbiology 159. Iwona Gientka, Stanisław Błażejak, Stanisław Błażejak, Lidia Stasiak, Lidia Stasiak, Anna Chlebowska-Śmigiel, Anna Chlebowska-Śmigiel1 (2012): 25–29. 2015Web.]</ref>.

* It has been observed that ''Lactobacillus'' species can produce EPS (''Lactococcus lactis'', ''Lactobacillus delbrueckii'', ''Lactobacillus casei'', and ''Lactobacillus helveticus'') <ref name="ESP"></ref>. Some ''Oenococcus oeni'' strains can also produce EPS <ref>[https://pubmed.ncbi.nlm.nih.gov/19659698/ 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 wines. J Appl Microbiol. 2010 Feb;108(2):499-509. doi: 10.1111/j.1365-2672.2009.04449.x. Epub 2009 Jun 30. PMID: 19659698.</ref>. Some species of yeast can also produce EPS, including ''Candida'', ''Cryptococcus'', ''Debaryomyces'', ''Lipomyces'', ''Pichia'' <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/18130223887259672465980936763439/ Videos Zach Taggart. Milk the Funk Facebook group post on MTF of ropy beerEPS from yeast. 01/16/2019.]</ref>, ''Pseudozyma'', ''Rhodotorula'' and ''Sporobolomyces'' <ref name="Gientka_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>.

====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.]

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>.

A strain of See also:* [[Lactobacillus#Bacteriocins|''Pediococcus pentocaseusLactobacillus'' 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.bacteriocins]]</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" />.

===Other Metabolites===Izquierdo-Pulido et al. (1995) found that out of 35 samples of Spanish lagers contaminated with ''P. damnosusPediococcus'' can produce high amounts , 21 of diacetyl during lactic acid production <ref>[http://onlinelibrary.wiley.com/doi/them had final tyramine levels between 5-10.1046mg/j.1365-2672.2000.00956.x/pdf Identification l, 6 of pediococci by ribotyping. R. Satokarithem had no detected tyramine, T. Mattila-Sandholm and M.L. Suihko. Journal 8 of Applied Microbiology 2000them had high levels around 25 mg/l, 88, 260–265.]</ref><ref>[http://mmbr.asm.org/content/77/2/157.full The Microbiology with higher levels being correlated to higher cell counts of Malting and Brewing. Nicholas A. Bokulicha, and Charles W. Bamforth. June 2013.]</ref>. ''P. damnosus'' also produces an antimicrobial compound called pediocin PD-1, which can inhibit several bacteria spp including Pediococcus''O. oeni'' <ref>[http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2672.2001.01486.x/full Growth optimization higher levels of Pediococcus damnosus NCFB 1832 and the influence tyramine were associated with higher cell counts of pH and nutrients on the production of pediocin PDtyramine-1producing strains during smaller bench test fermentations as well. H.A. Nel1, R. Bauer, E.J. Vandamme There was no correlation between the presence of wild yeast and L.M.T. Dickstyramine production. Jan 2002.]</ref><ref>[http://www.ncbi.nlm.nih.gov/pubmed/15878403 Purification, partial amino acid sequence Filtration 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>. ''P. claussenii'' tends to produce a smaller amount pasteurization after fermentation had no effect on the levels of acetic acid than lactic acid tyramine in about a 1:3 ratio. ''P. damnosus'' tends to produce only lactic acid and no acetic acid the final beers <ref name="Geissler">[httphttps://wwwwatermark.sciencedirectsilverchair.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>, although some strains have been found to produce small amounts of acetic acid of around 1000362-300 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.2050028x-041659_2_175.2010.tb00393.x/abstract Isolation, Identification, and Characterisation of Beer-Spoilage pdf Biogenic Amine Changes Related to Lactic Acid Bacteria from Microbrewed Beer from Victoria, AustraliaDuring Brewing. Garry MenzMARIAI ZQUIERDO-PULIDO, Christian Andrighetto, Angiolella Lombardi, Viviana Corich, Peter Aldred, Frank Vriesekoop. 2010.]</ref>JUDIT FONT-FABREGAS, but significantly less than the total acetic acid often found in gueuze (around 700JOSEP-2200 ppm <ref>[http://www.horscategoriebrewing.com/2016/07/duivelsbierMIQUEL CARCELLER-ofROSA, ABEL MARINE-halle.html JansenFONT, Dave. Hors Category Blog. "Duivelsbier of Halle". 07/30/2016. Retrieved 01/31/2018.]</ref>) and Flanders reds (300CARMENVIDAL-2300 ppm <ref>[http://www.sciencedirect.com/science/article/pii/S0168160515301896 Microbial diversity and metabolite composition of Belgian red-brown acidic alesCAROU. Isabel Snauwaert, Sanne P. Roels, Filip Van Nieuwerburg, Anita Van Landschoot, Luc De Vuyst, Peter Vandamme. 20151995.]</ref>). ''Pediococcus'' also carry 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>

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 mL¹. 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" />.