Fermentations were conducted until there was no liberation of
CO2 bubbles. Enough agitation was provided by the liberation of
CO2 during fermentation and by circulation of the broth through
the plate heat exchangers. Temperature was maintained at 30 C.
New inoculum (30 g/L of pressed yeast LPB-SC) was added at the
beginning of each fermentation. Antifoam and dispersant agents
tested were AE-2002 and AD-1009, respectively. These products
consist of a mixture of silicon oil, solvents, emulsifying waxes
and tensioactive agents. Dispersant agent was added at the beginning
of feeding to avoid foam formation and antifoam was added to
break the formed foam after feeding. Best concentrations were
determined considering effect on foam reduction and cost. The fermented
broth was discarded after fermentation and treated as a
common effluent.