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===Environment and Survival===
Up until recently, ''Brettanomyces'' has been only occasionally identified on the skins of fruit (on the skins of cider apples and wine grapes for example) <ref name="smith_divol_2016"></ref><ref name="Schifferdecker" />, and is thought to disperse via insects such as bees and fruit-flies (called "vectors" in the scientific literature) <ref name="Steensels">[http://www.sciencedirect.com/science/article/pii/S0168160515001865 Brettanomyces yeasts — From spoilage organisms to valuable contributors to industrial fermentations. Jan Steensels, Luk Daenen, Philippe Malcorps, Guy Derdelinckx, Hubert Verachtert, Kevin J. Verstrepen. International Journal of Food Microbiology Volume 206, 3 August 2015, Pages 24–38.]</ref><ref>[https://www.ncbi.nlm.nih.gov/pubmed/18077036 Survival patterns of Dekkera bruxellensis in wines and inhibitory effect of sulphur dioxide. f Barata A, Caldeira J, Botelheiro R, Pagliara D, Malfeito-Ferreira M, Loureiro V. 2008.]</ref><ref>[https://www.ncbi.nlm.nih.gov/pubmed/12892920 Spoilage yeasts in the wine industry. Loureiro V, Malfeito-Ferreira M. 2003.]</ref>. More recently, techniques have been invented to more easily isolate ''Brettanomyces'' from nature, which might be because of a "VBNC" state <ref>[https://www.sciencedirect.com/science/article/pii/S0944501306000231?via%3Dihub Development of an enrichment medium to detect Dekkera/Brettanomyces bruxellensis, a spoilage wine yeast, on the surface of grape berries. Vincent Renouf, Aline Lonvaud-Funel. 2007. DOI: https://doi.org/10.1016/j.micres.2006.02.006.]</ref><ref>[https://www.frontiersin.org/articles/10.3389/fmicb.2019.00415/abstract Occurrence of Brettanomyces bruxellensis on grape berries and in related winemaking cellar. Francesca Comitini1, Lucia Oro, Laura Canonico, Valentina Marinelli, Maurizio Ciani. 2019. DOI: 10.3389/fmicb.2019.00415.]</ref>. See [[Wild_Yeast_Isolation#Wild_Brettanomyces|Wild ''Brettanomyces'']] for more information. However, the occurrence of ''Brettanomyces'' has been more commonly identified in industrial food processing areas (wine, beer, kombucha, soft drinks, dairy products, tea, sourdough, etc.) <ref name="Crauwels_2016">[https://academic.oup.com/femsyr/article-abstract/17/1/fow105/2670560/Fermentation-assays-reveal-differences-in-sugar?redirectedFrom=fulltext Fermentation assays reveal differences in sugar and (off-) flavor metabolism across different Brettanomyces bruxellensis strains. Fermentation assays reveal differences in sugar and (off-) flavor metabolism across different Brettanomyces bruxellensis strains. Sam Crauwels, Filip Van Opstaele, Barbara Jaskula-Goiris, Jan Steensels, Christel Verreth, Lien Bosmans, Caroline Paulussen, Beatriz Herrera-Malaver, Ronnie de Jonge, Jessika De Clippeleer, Kathleen Marchal, Gorik De Samblanx, Kris A. Willems, Kevin J. Verstrepen, Guido Aerts, and Bart Lievens. 2016]</ref>. For example, ''B bruxelensis'', ''B. anomala'', and ''B. custersianus'' have mostly been isolated from wine or beer production, while ''B. naardenensis'' has mostly been isolated from soda production <ref name="Tiukova_2019">[https://www.mdpi.com/2076-2607/7/11/489 Assembly and Analysis of the Genome Sequence of the Yeast Brettanomyces naardenensis CBS 7540. Ievgeniia A. Tiukova, Huifeng Jiang, Jacques Dainat, Marc P. Hoeppner, Henrik Lantz, Jure Piskur, Mats Sandgren, Jens Nielsen, Zhenglong Gu, and Volkmar Passoth. 2019. DOI: https://doi.org/10.3390/microorganisms7110489.]</ref>. ''Brettanomyces'' is not considered to be airborne; however, one study has demonstrated a very small amount of cells in the air at wineries where wine with ''Brettanomyces'' in it was being handled (most of the yeasts found in the air were ''Aureobasidium'' and ''Cryptococcus'', which aren't considered spoilage organisms in beer and wine). These set of studies also determined that very specific methodology was needed in order capture ''Brettanomyces'' from the air, and indicated that the yeast was "stressed". While it is possible for ''Brettanomyces'' to be briefly carried by gusts of air, it only happens in the vicinity where the ''Brettanomyces'' beer or wine is being bottled (more so) or is actively fermenting (less so) <ref>[http://www.sciencedirect.com/science/article/pii/S0956713513002284 Screening of yeast mycoflora in winery air samples and their risk of wine contamination. E. Ocón, P. Garijo, S. Sanz, C. Olarte, R. López, P. Santamaría, A.R. Gutiérrez. Food Control Volume 34, Issue 2, December 2013, Pages 261–267.]</ref>. Good cleaning and sanitation and cold temperatures should be employed to keep ''Brettanomyces'' from contaminating other equipment; however, flying insects are also a potential cause for contamination of ''Brettanomyces''.
''Brettanomyces'' is commonly isolated from the surface of wood structures within breweries, wineries, and sometimes cideries. These include structures such as wooden fermentation vessels, walls of the building, as well as the inside surface of wood barrels and actually buried within the wood of barrels. ''Brettanomyces'' has been easily cultured from within the wood of oak barrels up to 4 mm into the wood, and occasionally as deep as 5 to 8 mm, depending on the age and variety (slightly higher populations tend to survive in French oak over American oak, and one study found that the ''Brettanomyces'' was able to penetrate the French oak barrels up to 8 mm, while only penetrate American oak barrels up to 4 mm) of the barrel <ref name="Agnolucci_2017" /><ref name="Cartwright_2018">[http://www.ajevonline.org/content/early/2018/05/23/ajev.2018.18024 Reduction of Brettanomyces bruxellensis Populations from Oak Barrel Staves Using Steam. Zachary M. Cartwright, Dean A. Glawe, Charles G. Edwards. 2018. DOI: 10.5344/ajev.2018.18024.]</ref>, with the highest concentration of surviving cells being at the top staves where oxygen is more accessible (although Cartwright et al. found the opposite was true, perhaps due to methodology of sampling or a difference in SO<sub>2</sub> concentrations). Some strains are able to utilize the cellulose of the wood as a carbon source, and occasionally form pseudohyphae within the wood which expands the surface area of the cells allowing them more access to nutrients and allowing them to survive in nutrient deficient environments <ref name="Cartwright_2018" />. Ozone gas has been shown to be an effective way to kill ''Brettanomyces'' that is buried in the wood of oak barrels, but the ozone must be applied for an adequate time to allow for the ozone to diffuse into the oak. Ozone has also been shown to be an effective way of greatly reducing but not completely eliminating the number of ''Brettanomyces'' on wine grapes. Liquid ozone has been shown to be less effective at eliminating ''Brettanomyces''. Heating the inside of the oak barrels to 60°C for 20 minutes with hot water or steam has also been found to be an effective way of killing ''Brettanomyces'' within the wood of barrels (see [[Barrel#Sanitizing|Barrel Sanitation]] for information on pasteurizing barrels) <ref>[https://www.ncbi.nlm.nih.gov/pubmed/25989358 Heat inactivation of wine spoilage yeast Dekkera bruxellensis by hot water treatment. Fabrizio, Vigentini, Parisi,Picozzi, Compagno, Foschino. 2015.]</ref><ref>[https://www.sciencedirect.com/science/article/pii/S1466856417310068 Control of Brettanomyces bruxellensis on wine grapes by post-harvest treatments with electrolyzed water, ozonated water and gaseous ozone. Francesco Craveroa, Vasileios Englezos, Kalliopi Rantsiou, Fabrizio Torchio, Simone Giacosa, Susana Río Segade, Vincenzo Gerbi, Luca Rolle, Luca Cocolin. 2018. DOI: https://doi.org/10.1016/j.ifset.2018.03.017.]</ref>. Although the role of ''Brettanomyces'' appears to be limited in distillation, it has been isolated during the fermentation process of tequila making. It has also been isolated from drains, pumps, transfer hoses, and other equipment that is difficult to sanitize. The survivability of ''Brettanomyces'' has also partly been attributed to its ability to form a [[Quality_Assurance#Biofilms|biofilm]] (in particular ''B. bruxellensis''). Microorganisms that can form a biofilm are more resistant to chemical cleaning agents and sanitizers than those that don't. ''Brettanomyces'' has therefore been identified as a significant contaminate for breweries and wineries. Oak barrels from wineries with unsanitary practices, in particular, have been identified as common contamination sites for ''B. bruxellensis''. ''Brettanomyces'' is also commonly found in sherry, and is found (although only rarely) in olive production, lemonade, kombucha, yogurt, pickles, and soft drinks. ''B. anomalus'' and ''B. bruxellensis'' are generally found much more commonly than the other three species of ''Brettanomyces'' <ref name="smith_divol_2016">[http://www.sciencedirect.com/science/article/pii/S0740002016302659 Brettanomyces bruxellensis, a survivalist prepared for the wine apocalypse and other beverages. Brendan D. Smith, Benoit Divol. June 2016.]</ref>.
Unlike most genera of yeast, ''Brettanomyces'' has the characteristics of being very tolerant to harsh conditions, including high amounts of alcohol (up to 14.5-15% ABV <ref name="Crauwels1" /><ref name="Agnolucci_2017" />), a pH as low as 2 <ref>[http://www.winesandvines.com/template.cfm?section=news&content=141954 Wines and Vines. New Research on Role of Yeast in Winemaking; report on a presentation by David Mills and Lucy Joseph from UC Davis. 11/14/2014. Retrieved 08/16/2015.]</ref>, and environments with low nitrogen <ref name="Schifferdecker"></ref> and low sugar sources <ref name="Smith_2018">[https://www.sciencedirect.com/science/article/pii/S0740002017308249 The carbon consumption pattern of the spoilage yeast Brettanomyces bruxellensis in synthetic wine-like medium. Brendan D.Smith and Benoit Divol. 2018. DOI: https://doi.org/10.1016/j.fm.2017.12.011.]</ref>. It has been reported that some strains require a very low concentration of fermentable sugars (less than 300 mg/L) and nitrogen (less than 6 mg/L), which is less than most wines contain <ref name="Smith_2017">[https://www.sciencedirect.com/science/article/pii/S0740002017308249 The carbon consumption pattern of the spoilage yeast Brettanomyces bruxellensis in synthetic wine-like medium. Brendan D. Smith, Benoit Divol. 2017.]</ref>. Some strains are able to utilize ethanol, glycerol, acetic acid, and malic acid when no other sugar sources are available <ref name="Smith_2018" />. This capability allows ''Brettanomyces'' to survive in alcoholic beverages such as beer, wine, and cider. In alcoholic beverages, ''B. bruxellensis'' tends to lag after the primary fermentation with ''Saccharomyces''. It is believed that during this lag phase, ''B. bruxellensis'' adapts to the harsh conditions of the beverage (low pH, high concentrations of ethanol, and limited sugar/nitrogen sources). After this lag phase, ''B. bruxellensis'' can grow and survive when no other yeasts can. ''Brettanomyces'' is also more resistant to pH and temperature changes, and tolerant of environments limited in oxygen (although ''Brettanomyces'' prefers the availability of at least a little bit of oxygen). Scientifically, which specific nitrogen and carbon sources ''B. bruxellensis'' uses in these stressful environments has not received much research <ref name="smith_divol_2016"></ref>. [https://www.winesandvines.com/news/article/200000/New-Tools-to-Limit-Wine-Spoilage One study from Dr. Charles Edwards] found that a combination of keeping wine under 54°F (12.2°C) and alcohol at or above 14% resulted in a decline of ''B. bruxellensis'' populations for up to 100 days for two strains that were tested. The study found that neither of the strains grew well at 14% and stopped growth completely at 16% ABV in wine, but one strain grew better than the other at 15%, demonstrating the genetic diversity of ''Brettanomyces''. The researchers concluded that a combination of high ethanol and cold temperatures as well as sulfur dioxide, chitosan, and filtration could be used to control ''Brettanomyces'' in winemaking. ''Brettanomyces'' has been found to be able to grow at temperatures as low as 50°F (10°C) and as high as 95°F (35°C); see [[Brettanomyces#Carbohydrate_Metabolism_and_Fermentation_Temperature|fermentation temperature]] for more information <ref>[http://www.ajevonline.org/content/early/2017/01/05/ajev.2017.16102 Interactions between Storage Temperature and Ethanol that Affect Growth of Brettanomyces bruxellensis in Merlot Wine. Taylor A. Oswald, Charles G. Edwards. 2017.]</ref>.
The genetic diversity of ''Brettanomyces'' is particularly wide. For example, one study that analyzed the whole genomes of 53 strains of ''B. bruxellensis'' found that the overall genetic diversity between different strains of ''B. bruxellensis'' was higher than strains of ''S. cerevisiae'' (however, the entire gene set, known as the ''pangenome'', of all the genes among all of the strains of '''B. bruxellensis'' is much smaller than the entire gene set of ''S. cerevisiae'') <ref name="Gounot_2019" />. Some studies have indicated that strains of ''B. bruxellensis'' have adapted to specific environments. For example, one study found that strains of ''B. bruxellensis'' isolated from wine had 20 genes involved in the metabolism of carbon and nitrogen, whereas strains isolated from beer did not. This indicated that ''B. bruxellensis'' strains living in wine have adapted to the harsher environment of wine <ref name="smith_divol_2016"></ref>. Another study found that one out of the two strains tested that were isolated from soda could not ferment maltose, and only strains isolated from wine were able to grow in wine and the beer/soda strains did not. The wine strains were also more resistant to sulfites, which are commonly used in the wine industry to prevent microbial contamination <ref name="Crauwels_2016" />. The whole genome sequencing of one strain of ''B. naardenensis'' and lambic strains of ''B. bruxellensis'' found that it was they are missing the genes associated with nitrate utilization, indicating that it the assimilation of nitrates is not well adapted required to survive in beer where nitrates are abundant due to hops , perhaps because of the abundance of nitrogen from other sources found in beer <ref name="Tiukova_2019" /><ref name="colomer_2020_genome" />.
The addition of vitamins can have a positive impact on ''Brettanomyces'' growth. For example, while ''Brettanomyces'' does not need riboflavin (vitamin B2) or thiamine (vitamin B1) in order to grow, the presence of either or both of these two vitamins encourages ''Brettanomyces'' growth <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>. Other vitamins such as p-aminobenzoic acid (PABA), folic acid (vitamin B9), nicotinic acid (vitamin B3), pantothenic acid (vitamin B5) are also not required for most strains of ''Brettanomyces'' to grow. The presence of alcohol can increase the dependence on vitamins for some strains of ''Brettanomyces'' to grow. For example, Myo-inositol (vitamin B8) and thiamine (vitamin B1) were required by two strains of ''B. bruxellensis'' when grown in 10% ethanol but not in 0% ethanol. Biotin (vitamin B7) is the one exception, and it was found that the lack of biotin inhibited the growth of some strains of ''B. bruxellensis''. Other studies contradict these previously mentioned findings, showing that thiamine was not required by the strains of ''B. bruxellensis'' tested, that pyridoxine was required, and biotin was not required. These discrepancies between scientific studies are probably due to the genetic differences between the strains selected, the growth media chosen by the scientists, and/or the growth conditions <ref>[http://www.mdpi.com/2311-5637/2/3/17 Use of Nutritional Requirements for Brettanomyces bruxellensis to Limit Infections in Wine. Nicolas H. von Cosmos and Charles G. Edwards. 2016.]</ref>.