The effects of pretreatments applied to raw materials and microorganism
selection in lignocellulosic bioethanol production were investigated. It has
been found that the yield of enzymatic pretreatment process applied after the
chemical pretreatment is about 4 times higher than that only chemical.
Enzymatic pretreatment used process yield is 3.5 times higher than that
chemical pretreatment. When the microorganism ethanol production yield values
of Saccharomyces cerevisiae and Pichia stipitis were examined, it was
found that S.cerevisiae was superior
to P.stipitis in chemical pretreated
reactors (about 1.7 times higher) while P.
stipitis’ yield was higher about 1.2 times in enzymatic pretreated
reactors. When the reactors which have been pretreated with both chemical and
enzymatic hydrolysis and P. stipitis
and S. cerevisiae used separately were
examined, it was observed that there was not a great difference in terms of
ethanol production yield. C. thermocellum’s
ethanol yield was found about 3 times lower than the S. cerevisiae and P.
stipitis. According to the obtained data, it was seen that S. cerevisiae could produce ethanol with
higher efficiency than P. stipitis.
At the same time, the difficulty of C.
thermocellum’s production conditions, high energy demand and high risk of
contamination, and low ethanol production yield, it is thought that it can only
be used in the research phase for now. But in particular, by investigating
extracellular cellulase enzyme system of C.
thermocellum, genetic modifications are predicted to play an important role
in the future in the second generation bioethanol production process.
Clostridum thermocellum, Saccharomyces cerevisiae, Lignocellulosic ethanol, Pichia stipitis, Pretreatment