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update to taxonomy information
Recently a new species of ''Brettanomyces'' has been proposed, although classification has not been fully established. The proposed name is ''Brettanomyces acidodurans'' sp. nov. Two strains of ''B. acidodurans'' were isolated from olive oil from Spain and Israel; however, its presence in olive oil has been described as "rare" because only two strains were found after searching dozens of olive oils. Its closest relation is to ''B. naardenesis'' by 73% of its genetic makeup. No teleomorph form was observed. This species is a strong acetic acid producer, and it is very tolerant of acetic acid in its environment. It can consume lactose and cellobiose but does not consume maltose. it is unknown but a possibility that this species contributes to the vinegary taste of spoiled olive oils, although this has generally been attributed to acetic acid bacteria <ref>[https://www.ncbi.nlm.nih.gov/pubmed/28160110 Brettanomyces acidodurans sp. nov., a new acetic acid producing yeast species from olive oil. Péter G, Dlauchy D, Tóbiás A, Fülöp L, Podgoršek M, Čadež N. 2017.]</ref>.
A genetic survey of 145 different strains of ''B. bruxellensis'' from 29 countries, 5 continents, and 9 different fermentation niches was conducted in 2018 by Avramova et al. They found that these strains formed roughly 6 genetic groups with mostly separate ancestral lineages, and 1 group with a mixed ancestral lineage: 3 wine groups, 1 beer group, 1 kombucha group (most distantly related to the beer group), as well as 1 tequila/ethanol group that has multiple ancestral lineages <ref name="Avramova_2018" />. These groups are partially determined by the identification of at least two hybridization events that happened during the evolution of ''B. bruxellensis'', similar to the hybridization events that created the Saaz and Frohberg subgroups of ''S. pastorianus'' (the parents of these hybridization events in ''B. bruxellensis'', whether from different species or not, has yet to be determined and will require whole genome sequencing of species closely related to ''B. bruxellensis'') <ref name="Gounot_2019" />. This was expressed mostly in the ploidy level of each group (the number of sets of chromosomes), with 2 of the wine groups, the tequila group, and the beer group containing more sets of chromosome pairs than the other groups (diploid vs triploid; this is thought to encourage adaption and hybridization). Additionally, the triploid wine group was generally more tolerant of SO<sup>2</sup> than the diploid wine groups <ref name="Avramova_2018" />. [https://www.frontiersin.org/articles/10.3389/fmicb.2020.00637 Colomer et al (2020)] surveyed the whole genomes of 64 strains of ''B. bruxellensis'', 14 strains of ''B. anomalus'', 3 strains of ''B. custersianus', and 3 strains of ''B. naardenensis''. They broke the ''B. bruxellensis'' beer group into two clades: a "farmhouse" clade which comprised of strains of ''B. bruxellensis'' isolated from commercial craft beer breweries, and a "lambic" clade which comprised of strains isolated from spontaneously fermented Belgian lambic beers. There was also a subdivision of the lambic clade which comprised of strains of ''B. bruxellensis'' identified with various natural origins; ethanol plants, barrel-aged beers, and matured wines. This subclade was called "wild/wood" by the researchers. See [https://www.frontiersin.org/files/Articles/495404/fmicb-11-00637-HTML-r1/image_m/fmicb-11-00637-g002.jpg Figure 2 (family tree)] from the study.
===Morphology===