3.3. Effects of temperature and time
The effects of acid concentration and temperature on the yield of
ethanol are shown in Fig. 3. It was observed that when the levels oftemperature increased the hydrolysis results a higher yield of
ethanol. However, from the graph following an increase of temperature,
the yield of ethanol decreased. This result might be due to
the possible formation of other molecules instead of the glucose
formation due to high temperature [23]. Similarly, at low and high
time, the yield of ethanol decreased. The response surface plot
obtained from the hydrolysis time and the hydrolysis temperature
was conical in shape, which defines the optimum operating conditions.
When a rotten banana was used for the bioethanol production,
the concentration increased at 35 C, 30 C and 23 C at
concentrations of 6.21, 5.88 and 5.39% (v/v), respectively [24].