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[[File:Pedio sugars.JPG|thumb|''Pediococcus'' fermentables based on species; table from [https://www.springer.com/us/book/9780387333410 "Wine Microbiology. Practical Applications and Procedures.", Kenneth C. Fugelsang, Charles G. Edwards, 2007.]]]
''P. damnosus'' can ferment glucose, sucrose, and fructose. Some strains of ''P. damnosus'' can ferment maltose, sucrose, and galactose <ref name="ucdavis"></ref><ref name="Oevelen_1979" />. 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 compounds. Compared to the microbe ''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. 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 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>[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, V. Jiranek. 2005. DOI: 10.1111/j.1365-2672.2005.02707.x.]</ref>. Some strains of ''P. damnosus'' found in lambic have been found to contain the genetic capability of breaking down ferulic acid into 4-vinylphenol, which can assist in ethyl 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===
The presence of beta-glucans from barley have been observed to extend both the growth 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>. 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'' and EPS was produced. The ''L. plantarum'' 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, 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>[http://www.mdpi.com/1422-0067/18/7/1588/htm In Situ β-Glucan Fortification of Cereal-Based Matrices by Pediococcus parvulus. 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 EPS genes 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. DOI: https://doi.org/10.1094/ASBCJ-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 ''Pediococcus 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, the beta-glucan "coat" disappeared from the cell walls and the lysozyme was once again effective at killing this strain of ''Pediococcus'' <ref>[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, Joana et al. “Lysozyme Resistance of the Ropy Strain Pediococcus Parvulus IOEB 8801 Is Correlated with Beta-Glucan Accumulation around the Cell.” International Journal of Food Microbiology 159.1 (2012): 25–29. Web.]</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/2465980936763439/ Zach Taggart. Milk the Funk Facebook group post on EPS 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====
Izquierdo-Pulido et al. (1995) found that out of 35 samples of Spanish lagers contaminated with ''Pediococcus'', 21 of them had final tyramine levels between 5-10 mg/l, 6 of them had no detected tyramine, and 8 of them had high levels around 25 mg/l, with higher levels being correlated to higher cell counts of ''Pediococcus''. higher levels of tyramine were associated with higher cell counts of the tyramine-producing strains during smaller bench test fermentations as well. There was no correlation between the presence of wild yeast and tyramine production. Filtration and pasteurization after fermentation had no effect on the levels of tyramine in the final beers <ref>[https://watermark.silverchair.com/0362-028x-59_2_175.pdf Biogenic Amine Changes Related to Lactic Acid Bacteria During Brewing. MARIAI ZQUIERDO-PULIDO, JUDIT FONT-FABREGAS, JOSEP-MIQUEL CARCELLER-ROSA, ABEL MARINE-FONT, and CARMENVIDAL-CAROU. 1995.]</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="Roosa_2024"/>.
See also: