Showing papers on "Fusel alcohol published in 1977"

Keto Acid Decarboxylase and Alcohol Dehydrogenase Activities of Yeast in Relation to the Formation of Fusel Alcohols

Abstract: Formation of fusel alcohols during the course of fermentation is a direct consequence of amino acid and carbohydrate metabolism which give rise to alpha-keto acid intermediates. When L-threonine, L-valine, L-isoleucine or L-leucine was used as the sole nitrogen source of an ale yeast growth medium, enhanced production of the corresponding fusel alcohol (n-propanol, isobutanol, 2-methyl-1-butanol or 3-methyl-1-butanol) was detected. An attempt is made to assess the ability of these yeasts to produce the aliphatic higher alcohols in terms of their specific keto acid decarboxylase and alcohol dehydrogenase activities in the yeast cell-free extract. Results show that, in most cases, there is a positive correlation between the enzyme activities and the production of individual fusel alcohols. Threonine-grown yeast does not show enhanced alpha-ketobutyric acid decarboxylase nor n-propanol dehydrogenase activities. For the first time, a very sensitive fluorometric method for measuring specific keto acid decarboxylase activity is described.