In this project we investigated the growth and off-flavor production of the potent wine spoilage yeast Brettanomyces bruxellensis. We analyzed growth and production of three dominant offflavor compounds 4-ethyl catechol, 4-ethyl guaiacol, and 4-ethyl phenol in model wine media in the presence of; 1) various concentrations of ethanol, 2) various sources of nitrogen, 3) various amounts of organic nitrogen, and 4) various types and amounts of residual sugars. This investigation was carried out with five strains of B. bruxellensis isolated from wine. The increased ethanol concentration affected the cell growth of all the strains and two strains did not show growth when the alcohol was above 12%and 13%respectively. The production of ethylphenol was affected too and diminished at the increase of ethanol concentration from 11%to 14%. Only 4-ethyl phenol was produced. The growth of B. bruxellensis was diminished in the absence of amino acids but, importantly, B. bruxellensisgrew with as little as 0.5 mg/L of diammonium phosphate (DAP) and no amino acids. Various amounts of nitrogen did affect the ethyl phenol production, yet, the production of ethyl phenols seems to be more strain dependent. More ethyl phenols were produced when only DAP was present. The presence of C6 (hexoses) and C5 (pentoses) sugars affected the yeast growth and the amounts of the ethyl phenols produced. When no C5 or C6, or only C5 sugar were present, the total amount of ethyl phenols was lower (except with strain CE116) and a lower cell density was observed. The presence of only C5 sugar sugars enhanced the production of 4-ethyl guaiacol (except for strain 2091). In the presence of only amino acids as a nitrogen source, all the strains grew when as little and 50 mg/L of total amino acids were added to the medium.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF2006-10-16 12:32:052019-01-22 18:16:28Characterization of Volatile Phenois and Related Enzyme Activity in Brettanomyces Wine Strains