3.4. Effect of temperature and acid concentration
The effect of temperature and acid concentration is shown in
Fig. 4. It was found that the lower and higher levels of temperature
and acid concentration, the production of ethanol yield decreased.
This result may be due to effect of the hydrolysis treatment. At
lower temperature and acid concentration the cellulose might not
hydrolysis to simple glucose, and at higher acid concentration and
time the cellulose might convert to other molecules which might
not be fermentable [25]. Hence, both temperature and acid concentration
have a strong relationship for the yield of ethanol production.
The hydrolysis temperature increases at lower levels of
acid concentration, and increased levels of acid concentration at
lower level of temperature produce a positive effect on the yield of
ethanol. The response surface suggests that there was a dominance
interaction of these two factors [26].