The production of ethanol was recorded every 24 h for 96 h.
Fig. 2c is the result of ethanol production at a various range of overliming
pH. The highest amount of ethanol was produced within
48 h of incubation time. The sharp drop of ethanol concentration
after 48 h of incubation suggests that ethanol may be oxidized into
acetaldehyde or acetate (Zakhari, 2006). Moreover, ethanol, the
product from fermentation, is also the inhibitor for ethanol production
(Taherzadeh and Karimi, 2011). The rapid decrease of ethanol