Finally, we attempted SSF of EFB using Penicillium sp. TG2
cellulolytic enzymes and the yeast K. marxianus CBS1555 under the
conditions described in the “Materials and methods”. The conversion
yield to ethanol from alkali-pretreated EFBs was just 7.8%, due
to the low level of saccharification yield of EFB (Fig. 8). Although
Penicillium sp. TG2 cellulolytic enzymes showed high activity on
cellulosic material such filter pater comparable to a commercial
enzyme CTec2 (Novozyme), the low activity on EFBs is likely to be
caused by the presence of lignin material in the industrial cellulosic
material. The higher activity shown by commercial enzymes might
be due to the presence of additives such as hydrophobin, which
accelerates the hydrolysis of lignocellulose. However, Penicillium sp.
TG2 cellulolytic enzymes showed the similar activity to the lignocellulosic
material compared to those of T. reesei RUT-C30 (data not
shown), indicating that the strain has a commercial potential.