demand because of lack of the starch gelatinization and liquefaction
steps. Also some improvements for direct conversion of starch
to ethanol technology were done. Balcerek and Pielech-Przybylska
[22] studied, among other, the effect of thermal prehydrolysis of
triticale meal using a-amylase and application of protease on the
process of raw starch hydrolysis and fermentation. They discovered
that better efficiency of fermentation was obtained without
thermal activation but with added proteolytic enzyme. Montalbo-
Lomboy et al. [23] studied the effect of sonification of corn
meal slurry prior to direct conversion to ethanol. The results of this
research proved that sonification of raw material improved the
ethanol yield by ca. 20% in comparison to the control samples,
moreover the ethanol yield in sonificated samples was similar to
jet-cooked corn meal. The authors also conducted the economical
evaluation and energy usage for jet-cooking and ultrasonics installations
in industrial environments. They stated that the overall cost
for installation and maintenance for ultrasonic apparatus is lower
in comparison to hydrocooking, also the energy analysis proved
that much less energy is needed for sonification of raw material
than for jet cooking. Also microwave treatment improves enzymatic
hydrolysis of starch [24].