ESTERASE ACTIVITY IN THE GENUSBRETTANOMYCES

Abstract

During the spontaneous fermentation of Iambic and the production of the typical Belgian beer Gueuze, yeasts of the genus Brettanomyces are always found. They are especially active in the 6 to 12 months fermentation period and during refermentation in the bottle. It was found that Brettanomyces yeasts show esterase activity towards a large number of esters but especially towards esters normally found in Gueuze: ethyl acetate, ethyl lactate, /so-amyl acetate and phenethyl acetate. The esterase activity is expressed by whole cells of all Brettanomyces strains in our collection, but not by Saccharomyces or Kloeckera. The enzyme is partially purified by ammon ium sulphate precipitation. It shows optimal activity at pH 7-6 for the hydrolysis of ethyl acetete and relative good stability at around 2°C. Levels of whole cell esterase activity are dependent on growth medium, aeration rate and temperature. Most interesting is the ester-synthesising activity of this esterase. Its role and influence on the ester fraction of Iambic and Gueuze seem very likely, which may then be considered as the first confirmed function of Brettanomyces during this special fermentation process.

Brettanomyces bruxellensis, a survivalist prepared for the wine apocalypse and other beverages

“…There are many complex alterations to the flavour profile that occur and the effect on the resulting beer is 2 fold. An example of such an alteration is a cellbound esterase that changes the ester profile of the beer (Spaepen and Verachtert, 1982). In beer, Brettanomyces yeasts and Pediococcus bacteria are the main microorganisms responsible for volatile phenol production (Spaepen et al, 1981;Thurston and Tubb, 1981;Martens et al, 1997).…”

Microbial acidification, alcoholization, and aroma production during spontaneous lambic beer production

“…Brettanomyces species are responsible for the further attentuation, and even over‐attenuation, and unique flavor (unique phenolic compound and ester profiles) of lambic beer. Thanks to their nutritionally efficient metabolism, Brettanomyces species are capable of surviving the harsh conditions during the long‐lasting lambic beer production process, while Saccharomyces species cannot . The most isolated Brettanomyces species prevailing during lambic beer maturation are B. bruxellensis and Brettanomyces lambicus , which were later found to represent the same species, hence the latter has been reclassified as B. bruxellensis .…”

Evaluation of  the glycoside hydrolase activity of aBrettanomycesstrain on glycosides from sour cherry (Prunus cerasusL.) used in the production of special fruit beers

“…Benzaldehyde can be released from the cyanogenic glycosides amygdalin and prunasin. Brettanomyces species are known for an esterase activity catalysing the synthesis and hydrolysis of ethyl acetate, ethyl lactate, isoamyl acetate and phenyl ethyl acetate, until equilibrium concentrations are reached (Spaepen & Verachtert, 1982). The latter is further hydrolysed by prunasin hydrolase (EC 3.2.1.118) to glucose and mandelonitrile.…”