3.4 The production of ethanol and hydrogen from immobilized cell technique
Traditional fermentation systems use freely suspended bacterial cells in a batch bioreactor. However,
the production from free cells is relative low. Immobilizing bacterial cells on several support types can
provide high cell densities in the bioreactor according to high productivity. Various immobilization methods are available to researchers and the nature of the application often dictates the choice. Loofah
sponge, is a natural material, was selected as supporter in this study. Bacterial cells prepared as describe
above were attachment on the surface of this materials.
This study indicated that biofuel production were increased (>1.2-folds) by immobilized cell
technique. The immobilized S. cerevisiae yielded highest ethanol (11.63 g/L) after 72 h of cultivation
(Fig. 2a). The similar trend was also observed by immobilized E. aerogenes while the production of
ethanol and hydrogen were also increased to 1.66 g/L and 1,759 mL/L, respectively (Fig. 2b). The
comparison between the production of biofuel from free cell suspension and immobilized cell was given
in Table 4.