in comparison to microwave, ultrasonic and unpretreated variants
of the experiment, what suggests that application of relatively
low-temperature and short time enzymatic hydrolysis (unlike in
the SHF process) of waste bread for direct conversion to ethanol
using GSHE could be used in fermentation of media at higher solids
loading than in present study (150 g kg1) avoiding the problem of
water binding capacity of raw material. Montalbo-Lamboy et al.
[23] studied the effect of batch and continuous ultrasonic pretreatment
of corn slurry prior to GSHE aided fermentation. They discovered
that both batch and continuous method increased the initial
concentration of glucose in raw material slurries, what was probably
caused by starch gelatinization during pretreatment. Sadeghi
and Shawrang [24] studied the effect of microwave irradiation on
rumen degradability of corn meal. They found that irradiation of
raw material for 3 to 5 min at 800W power input increased starch
degradation rate. In present experimental conditions no effect of
ultrasonic and microwave pretreatment on initial sugar release
and liquefaction of waste bread was observed. This was probably
caused by the physico-chemical alterations of bread ingredients