Elucidation of the Role of Nitrogenous Wort Components in Yeast Fermentation

The Free Amino Nitrogen (FAN) content of wort prescribes efficient yeast cell growth and fermentation performance. FAN consists of the individual amino acids, small peptides and ammonia ions formed during malting, the relative amounts of which vary. In this paper, the individual constituents of FAN were dissected and their effect on both ale and lager fermentations determined. The patterns of amino acid and small peptide uptake and the changes in extracellular protease activity revealed the dynamic environment that develops during fermentation. Lysine and methionine, previously identified as key amino acids in wort fermentation, were investigated further.