Abstract Palm pressed fiber (PPF) is a clean and renewable
lignocellulosic material. The PPF and delignified PPF (DPPF) were used
as a carrier for immobilization of Candida shehatae TISTR5843 in
bioethanol production. PPF was pre-treated by milling to obtain small
particles, whereas DPPF was the delignification of PPF using NaClO2. C.
shehatae TISTR5843 was grown in modified yeast extract- malt (YM)
medium at 30 \ub1 2\ubaC on an orbital shaker at 150 rpm for batch
and repeated batch fermentation. In the batch system, immobilized cells
on a small size, less than 0.5 mm, of DPPF (sDPPF) gave the maximum
ethanol production of 11.5 g L-1 at 24 hrs cultivation period. The
ethanol concentration and ethanol yield of sDPPF were 6.2% and 6.8%
higher (ethanol production 11.5 g L-1, ethanol yield 0.47 g g-1) than
those of free cells (ethanol production 10.8 g L-1, ethanol yield 0.44
g g-1) after 36 hrs of cultivation. In contrast, the small size of PPF
(sPPF) was selected as a carrier in repeated batch fermentation for
cost effectiveness. The ethanol productivity of immobilized yeast cells
in repeated batch fermentations was 45.2-51.6% greater than that
obtained from batch fermentations. The immobilized cells on sPPF
improved the ethanol production and could be reused 4 times with
retaining the activity of 93%. In conclusion, PPF is a potential
carrier in the immobilization system. The pre-treatment of PPF
increases the surface area that enhances cell adsorption and ethanol
production by C. shehatae TISTR5843