This is an interesting result because gas produc-
tion experiments showed that CO2 production ceased after 7 days
(Figs. 5 and 6) and cultures were dormant for a long time before
starch breakdown commenced after 20 days incubation. When
the experiments were started with 10 ml yeast inoculum about
95% of total sugar and 70% protein were removed after a 25 day
incubation but yeast produced large amounts of CO2 only during
the first few days of the incubation (Figs. 5 and 6). CO2 gas production was high after 2 or 3 days but then rapidly declined to zero
due to the rapid digestion of easily metabolized organic compounds. Mobilization of starch only became apparent after more
than 20 days incubation but it was interesting that little or no
CO2 was produced as a result of this late mobilization of starch.
Glucose would have been the breakdown product of starch
hydrolysis by the a-glucoamylases but no significant amounts of
CO2 was being produced by conversion of pyruvic acid into alcohol
and CO2.