2.3. Use of the yeast S. cerevisiae A2 to scale up the process in a 10L
bioreactor
The proliferation of the yeastS. cerevisiae A2, isolated from
sugarcane molasses was carried out in a 10 L Bioreactor Model N
:
MF-214 (New Brunswick Scientific CO. INC., Edison: New Jersey,
USA). The bioreactor was inoculated with 250 mL ofS. cerevisiaeA2
suspension (1.1410
4
cel/mL), obtained after 12 h incubation in a
thermostatic bath at 30
C, 150 rpm, and 2.5 vvm oxygen. In order
to maximize the proliferation of biomass and minimize the formation of ethanol, the process was conducted using a fed-batch
process, where the sucrose present in the YPS proliferation medium was added intermittently, starting with 20 g/L inside the
reactor and adding three consecutive pulses of 10 g/L after 4, 8 and
12 h.