The high initial concentration of substrate (40 g of
starch/L) in the media favored cell growth, as the production
of both enzymes. Although the maximum level
of amylase was reached in BW medium (70.29 EU/
mL), which was higher than in MPW medium
(60.12 EU/mL), the maximum protease levels (ffi6 EU/
mL) were similar in both media.
During fermentation, the pH initially dropped from
6.0 to 4.0 after 24 h followed by its increase to 7.4
approximately (48 h), and remained constant thereafter.
The concentration of total sugars, nitrogen and phosphorous
decreased during fermentation, coinciding with
an increase of biomass and enzyme production leading
to a final COD of 0.24 g/L (in the media supplemented
with 40 g of starch/L) or lower (in the media with lower
initial starch concentrations). This indicates that at least
92% and 93% of the initial COD were removed from the
brewery and meat processing wastes, respectively.