The activity of the NAD-specific alcohol dehydrogenases
(ADHs) of S. cerevisiae was determined during production
of alcohol-free beer (Fig. 3). The activity decreased
substantially, especially during the first 5 days. ADH activity
was also determined in batch grown cells under anaerobic
conditions. Here, activity was approximately 0.2 U/mg
protein, which was similar to the activity detected in immobilized
cells at the end of the production period (Fig. 3).