However, a decreasing trend in ethanol concentration appeared at
37 C. When the fermentation temperature was further increased
to 39 C, ethanol concentration and yeast cell viability decreased to
approximately 40 g L1 and 53%, respectively. As shown in Fig. 5,
temperature negatively influenced cell activity, and lack of activity
at 37 C led to decrease in ethanol concentration. The cell activity at
39 C was slight higher than that at 37 C due to lower ethanol
concentration that alleviated the inhibition effect on yeast cells.
Performing the continuous ethanol fermentation at 35 C, an ethanol concentration of (70.7 ± 0.8) g L1 was obtained, corresponding to ethanol yield of 89.8% and productivity of
21.2 g L1 h1.