INFLUENCE OF THE CONCENTRATION OF BRANCHED CHAIN AMINO ACIDS ON THE FORMATION OF FUSEL ALCOHOLS

Abstract

The influence of concentrations of branched‐chain amino acids on the total, anabolic and catabolic production of isobutyl, active amyl, and isoamyl alcohol by Saccharomyces cerevisiae X 2180‐1A has been examined in media with high nitrogen levels. It has been found that the total and catabolic production of higher alcohols increased with increasing concentrations of the corresponding amino acids. The anabolic pathway can be suppressed by high levels of the corresponding amino acid. Lower concentrations up to 1 mm for isoleucine and 10mm for leucine stimulate the anabolic formation of active amyl alcohol and isoamyl alcohol respectively. From the data obtained, it is shown that, under the conditions used, 50% or more of the fusel alcohols may arise in a beer wort fermentation from carbohydrates. 1978 The Institute of Brewing & Distilling