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Brettanomyces

298 bytes added, 17:43, 12 May 2016
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===Carbohydrate Metabolism===
''Brettanomyces'' strains may possess both alpha and beta glucosidases. These enzymes allow ''Brettanomyces'' strains to break down longer chain carbohydrate molecules (including maltose, sucrose, starch, and cellulose) and to liberate glycosidically bound sugars which are unfermentable to ''Saccharomyces'' yeasts <ref>[http://www.scribd.com/doc/277758178/Insight-into-the-Dekkera-anomala-YV396-genome Insight into the Dekkera anomala YV396 genome. Samuel Aeschlimann. Self published on Eureka Brewing Blog. Spet 2015.]</ref>. Extracellular and intracellular alpha-glucosidase activity has been shown to break down sugars up to 9 carbons in one strain of ''B. lambicus'', which is partly responsible for the over-attenuation of wort that some strains of ''Brettanomyces'' an achieve <ref name="yakobson_introduction"></ref>.
Glycosides are sugar molecules connected to other organic compounds such as acids, alcohols, and aldehydes which are flavor and aroma inactive due to the sugar molecule attached. By cleaving off the sugar molecule through glucosidase activity, ''Brettanomyces'' species can liberate these compounds (called aglycones) into their aroma-active and flavor-active states, or states that may become flavor and aroma active through further modification<ref>Daenen et al., 2008. Evaluation of the glycoside hydrolase activity of a Brettanomyces strain on glycosides from sour cherry (Prunus cerasus L.) used in the production of special fruit beers. FEMS Yeast Res. 8, 1103-1114.</ref>. Therefore ''Brettanomyces'' strains are able to produce novel flavors and aromas from hops, fruits, and fruit pits that ''Saccharomyces'' yeasts cannot produce. In addition, the liberated aroma and flavor active compounds may be further processed by ''Brettanomyces'' through ester production or destruction pathways. See [[Brettanomyces#Glycosides_and_Beta-Glucosidase_Activity|Beta-Glucosidase Activity]] for more information.

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