Saccharomyces brettanomyces

Agar gel is added to the nutrient medium to cul-mre yeast prior to counting. It is supplemented with biphenyl (0.015% in ethanol) to prevent mold development and 0.01% chloramphenicol to inhibit bacterial growth. Cycloheximide (0.1%) may be added to select non-Saccharomyces" Brettanomyces, etc.) yeasts, as they alone survive this treatment. The incubation period is around 2-3 days for the Saccharomyces genus and... 

Brewing yeasts contribute positively to beer mouth-feel by producing carbon dioxide and foam bubbles. The impact of yeasts on beer taste varies with the yeasts involved in beer fermentation. In the spontaneous fermentation of acidic beers such as lambics, the mn-Saccharomyces brettanomyces yeasts can ferment malto-oligosaccharides that... 

Acid formation Species of Brettanomyces, Hansenula, Pic Ilia, Saccharomyces As a contaminant in wines. Brettanomyces spp. Forms a higher concentration of volatile acids (also isobutyiic and isovaleric acids) than S. cerevisiae. Pichia species and other yeasts are responsible for acetic acid production in brines of domestic green olives not lactobacilli, as assumed for years (Vaughn et al., 1976). 

Turbidity formation In wine Saccharomyces bailii. S. chexalieri, Brettanomyces spp. In beer S. diastaticus, S. bayanus In soft drinks in wine S. bailli, S. chevalieri in beer. S. diastaticus, 5. bayannus. 

Daenen, L., Saison. D., Sterckx, F., Delvaux, E.R., Verachtert, H. DerdeUnckx, G. (2007). Scrre-nening and evaluationof the glucoside hydorlase activity of Saccharomyces and Brettanomyces brewing yeasts. J.Appl. Miocrobiol. doi 10.1111/J.1365-2672.2007.03566.X... 

Yeast differ in sensitivity to SO2 treatment in fruit juices and wines. Brettanomyces spp. can resist 500 mg/L SO2 while Pichia membranefaciens Kloeckera apiculata are less resistant (63). In general, many yeast and bacteria are inhibited by 100 mg/L and less SO2 (64). Beech and Carr (65) found low concentrations of molecular SO2 (0.625 mg/L) were toxic to species of the genera Brettanomyces and Saccharomyces. 

Yeasts (Saccharomyces sp., Hensenula Torulopsis Debaromyces Canada, Kluyveiomyces, Pichia and Brettanomyces... 

Each species is made up of one or more strains. For example, by November, 1972, only one strain of Brettanomyces abstinens had been reported. By contrast, very many strains are known of the baking and brewing species, Saccharomyces cerevisiae the 1970 edition of the catalogue of the National Collection of Yeast Cultures (NCYC)86 lists 357 strains of this species. A strain is a culture and its subcultures, derived from a single isolated cell (cf, Refs. 87 and 88). 

Finally, oxidation of hydroxycinnamoyl tartaric acid (HCTA) into hydroxycinnamic acids (HCA), and the successive decarboxylation operated by Saccharomyces yeasts, or reduction and decarboxylation by Brettanomyces yeasts, induce off-flavours due to vinyl phenols and ethyl phenols formation, respectively. 

Oligomer proanthocyanidins inhibit Saccharomyces cerevisiae cin-namate decarboxylase (Chatonnet et al., 1990), justifying the very low amounts of vinylphenols in red wines on the contrary, Brettanomyces decarboxylase is not inhibited by proanthocyanidines (Chatonnet et al.,... 

Table 8.5. Impact of polyphenols on the synthesis of volatile phenols by Saccharomyces cerevisiae and Brettanomyces intermedins (Chatonnet et al., 1992b)...

Alcoholic fermentation Beer Cereals (malt) Saccharomyces cerevisiae Brettanomyces bruxellensis Lb. brevis... 

Chardonnay and Sauvignon Blanc. Schanderl and Draczynski (1952) and, subsequently, Van de Water (1990) report isolation of Brettanomyces/Dekkera from methode champenoise sparkling wine en tirage. Van de Water further notes that both appear to be less sensitive than Saccharomyces to carbon dioxide and concludes that they may become a more widespread problem as California sparkling wine production increases. 

Other substrates present in wine and juice may be available to Brettanomyces as sources of carbon and nitrogen. Ethanol and ethyl acetate are assimilated aerobically and may represent sole carbon sources. Smith (1993) reports that D-proline represents a nitrogen source. Because this amino acid is not biologically available to Saccharomyces during the course of fermentation, it is normally present in wines at substantial levels (Zoeck-lein et al., 1995). 

Dubourdieu (1992) points out that wine yeasts Saccharomyces cerevisiae also contains the cinnamate decarboxylase and thus are capable of producing the vinyl phenol intermediate. However, flavonoid phenols (tannins) inhibit its activity hence, the formation of volatile phenols in red and rose wines is significantly less than that seen in white wine fermentations. Activity of cinnamate decarboxylase in the case of Brettanomyces and Dekkera, however, is not inhibited by polymeric phenols. 

WL is an acronym for the no longer extant Wallerstein Laboratories which originally marketed the media. Presendy sold through several suppliers, WL-differential (WLD) theoretically utilizes the selective properties of actidione for identification of resistant species in mixed populations (i.e., LAB in the presence of Saccharomyces, or Brettanomyces in a population of Saccharomyces). WLD is often used in conjunction with WL-nutritional (WLN) (without actidione) when total viable cell populations are monitored. Both media utilize the pH indicator, bromcresol green, which additionally permits rapid screening of acid-producing colonies (i.e., Brettanomyces). ... 

In particular, SO2 has been added to must for the last century to prevent the multiplication of, and hence spontaneous fermentation of juice by indigenous yeasts (Cruess, 1912). It has been demonstrated that if SO2 is absent from a must, indigenous yeasts predominate (Kunkee and Amer-ine, 1970). For example, if an adequate concentration of SO2 is not maintained, the indigenous yeast generus Brettanomyces can readily contaminate a winery, especially wine in storage barrels (Ough et aL, 1983). Presumably the origin of wild strains of Saccharomyces cerevisiae in wine is also the winery and its equipment (Martini and Martini, 1990). 

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