Overall, malic acid was produced from thin stillage
by the Aspergillus strains used in this study. Malic acid
production on the thin stillage was noted to be highest
for A. niger ATCC 9142 while the malic acid yield
from the glycerol in the thin stillage was observed to be
highest for A. niger ATCC 10577. Considering that
ethanol plants produce large volumes of thin stillage
each year, a process to use the available sugar and
glycerol in thin stillage to produce malic acid using the
A. niger strains has potential for the production of food
grade malic acid.