Palm pressed fiber (PPF) is a lignocellulosic material that has potential to be cheap substrate
for ethanol production. In this study, the enzymatic hydrolysis of alkali pretreated PPF was
investigated. It was found that the hydrolysis with cellulase (10 FPU g1 of PPF) and
b-glucosidase (10 U g1 of PPF) gave the higher reducing sugar production than using
cellulase alone. In addition, the optimum condition of simultaneous saccharification and
fermentation (SSF) with 6 h of prehydrolysis for ethanol production was the PPF concentration
of 100 kg m3 with the enzyme loading of cellulase 6.0 FPU g1 of PPF and b-glucosidase
3.0 U g1 of PPF at pH of 5.0 and 35 C. The ethanol concentration of 10.4 kg m3 and
ethanol yield of 192 g kg1 of cellulose was obtained at the optimum condition in 24 h of SSF.
Finally, the effect of prehydrolysis of pretreated PPF prior to SSF on the ethanol concentration
was examined with batch and fed-batch mode of hydrolysis. It was found that prehydrolysis
with the fed-batch mode did not improve ethanol yield. However, the fed-batch
mode of prehydrolysis gave the highest ethanol production of 12.1 kg m3 at 12 h of SSF
process. Also, it was concluded that the advantages of fed-batch of prehydrolysis prior SSF
were the less enzyme requirement and the increasing PPF loading for ethanol production.