in Fig. 1 with a third complete stirred tank reactor (R3), which is
used for the cultivation of yeast cells with high activity. The
continuous ethanol fermentation was started in the same manner
as described in Section 2.5.2. R10 was performed under the same
conditions as R1 in Section 2.5.2. Thick juice and tap water con
taining mineral nutrients were continuously and separately fed into
R3 at feeding rates of f31 and f32, respectively. Fermented mash in R3
was pumped into R20, and thick juice was fed into R20 at a feeding
rate of f20 at the same time. The sugar concentration in R10 (S10), R20
(S20) and R3 (S3) were kept at 140 g L1, 190 g L1 and 90 g L1,
respectively, assuming no sugar was consumed. The dilution rate of
R10 (D1) and R3 (D3) were kept at 0.2 h1 and 0.1 h1, respectively.
S10 was calculated according to Eq. (1). S20, S3 and D3 were calculated
as follows: