Conditions (3) and (4) yielded slightly higher ethanol concentrations than (1), viz. 6.17% (w/v) at 54 h and 6.03% (w/v) at 60 h, respectively, with similar productivities and percentages of theoretical yields. Although Condition (2) gave the
highest growth and although rapid growth was observed in the first 24 h the maximal growth measured as optical
density was only 12.73. Surprisingly, after 24 h, the viable cell count determined by methylene blue staining decreased
rapidly, and no viable cells could be detected at 54 h. Condition (1) batch fermentation yielded the lowest growth
among all conditions with OD at 5.83, and it consequently produced the lowest ethanol concentration, while (3) and
(4) gave maximal growths as determined by OD of only 8.92 at 36 h and 8.10 at 44 h, respectively