| Abstract: | The formation of higher alcohols by various yeasts has been studied as a function of the nitrogen level of the medium. Two types of substrate were used. In one ammonium sulphate was the sole nitrogen source and in the other a complex amino acid mixture simulating that present in brewery wort was used. In the former medium, the patterns exhibited by the yeasts were all very much alike, indicating that the formation of higher alcohols through the biosynthetic activities of yeasts is always basically similar. In the medium containing a complex mixture of amino acids, where the higher alcohols can be formed partly or entirely from the exogenous amino acids through Ehrlich's mechanism, widely different patterns were observed, indicating that the utilization of exogenous amino acids as a source of nitrogen and the extent of regulation of biosynthetic pathways vary with species and strain. All the brewery strains seem to be rather similar and no distinct differences between top and bottom fermentation strains could be observed. |
