Cs. Chen et al., ETHANOL FERMENTATION IN A TOWER FERMENTER USING SELF-AGGREGATING SACCHAROMYCES-UVARUM - BIOREACTOR PERFORMANCE, Applied biochemistry and biotechnology, 45-6, 1994, pp. 531-544
A self-aggregating strain of Saccharomyces uvarum (U4) was used as a b
iocatalyst to carry out continuous ethanol fermentation in a tower fer
menter equipped with a cell separator. Cell aggregates (2-3 mm) formed
a stable packed bed in the fermenter, and the cell separator retained
yeast cells effectively. Corn steep liquor was used as a nitrogen sou
rce for the fermentation of corn. syrup and black strap molasses. An e
thanol productivity of 54 g/L/h was reached using corn syrup at a dilu
tion rate of 0.7/h, and sugar concentration in the feed was 15% (w/v).
For molasses fermentation, an ethanol productivity of 22 g/L/h was ob
tained at a dilution rate of 0.7/h, and sugar concentration in the fee
d was 12.5% (w/v). Ethanol yields obtained from tower fermentation are
higher than those obtained from flask fermentation (96% for corn syru
p fermentation and 92% for molasses fermentation). No significant loss
in fermentation activity was observed after 3 mo of operation.