2.5. Ethanol yield and pretreatment efficacy calculations
The ethanol yield (h) was introduced to quantify the efficiency of
a process. The yield was calculated using the following equation
[12]:
hð%Þ ¼
ethanol concentration at the end of the experiment!
g
L
"
glucose concentration after the hydrolysis stage!
g
L
"
# 100
(1)
The second parameter used is the efficacy (x), which considers
the efficiency of the ith pretreated test compared with the one
obtained without any pretreatment. x was calculated as follows:
x ¼ hP / hNPah (2)
F. Battista et al. / Renewable Energy 88 (2016) 401e407 403
where hP is the efficiency obtained with the pretreated mixture and
hNPah is the efficiency obtained without any pretreatment after the
hydrolysis stage. When x is less than 1, the pretreatment lowers the
efficiency, and likely produces some inhibitory substances, whereas
when x is approximately 1, the pretreatment has no effect on the
fermentation, and finally, when x is greater than 1, the pretreatment
is able to increase the process efficiency