feeding pretreated Miscanthus into the HF tank via the continuous
feeding system was 8 h after the solid Miscanthus was liquefied
into a slurry state (Fig. 3).
Both the glucose consumption rate and the ethanol production
rate using the angled-type II were greater than that using other
impellers (Fig. 3). A glucose concentration of 67.2 ± 2.4 g/L was
obtained in the hydrolysate slurry using the standard type impeller,
and about 70.0 g/L was obtained with the angled impellers,
prior to inoculation. The ethanol concentration at the end of SSF
were 63.4 ± 1.0 g/L, 66.5 ± 1.3 g/L, 69.2 ± 1.6 g/L, and 66.0 ± 1.2 g/L
for the standard type, angled-type I, angled-type II, and angledtype
III impellers, respectively. Thus, the type of impeller used
had an effect on the SSF process. One side of the paddle pushed
the biomass up, and the other pushed the biomass down in the
reactor, which helped to mix the upper and lower biomass,
enzymes, and microorganisms. Using the angled-type of impeller
decreased the surface resistance of the paddle, and reduced the
power consumption required for agitation, as compared to that
required by the standard type of impeller.