The immobilization of Saccharomyces cerevisiae onto sugar beet pulp (SBP) by
natural adhesion is an efficient and low-cost method for retaining high
biocatalyst density in the ethanol fermentation system. In the present study,
cells of S. cerevisiae 163, were immobilized by natural adhesion onto SBP.
The retention of immobilized cells attained the level of about 1.7?1011
cells/gram of dry SBP. Continuous ethanol production from sugar beet thick
juice (TJ) was performed in a cylinder glass bioreactor at a temperature of
30?C and pH 5 during a 27-day period. The stability of the fermentation
process at dilution rate (D) of 0.025 h-1 and 0.05 h-1 was evaluated. The
yeast-SBP system was shown to be stable for over a 15-day period at the
dilution rate of 0.025 h-1, while the dilution rate of 0.05 h-1 was found to
be unsuitable due to the intensive yeast leaching from the support. At D of
0.025 h-1 the maximum sugar utilization (Su), ethanol concentration (P),
volumetric ethanol productivity (Qp), ethanol yield (Yp/s) and fermentation
efficiency were 97.1%, 54.7 g/l, 2.3 g/lh, 0.498 g/g and 97.6%, respectively.
The application of immobilized cells Saccharomyces cerevisiae for continuous ethanol production. II. Comparison of several alternatives of the continuous method.
