The effects of number of recycling cycles and cell
density on ethanol production during hydrolyzate fermentation
are summarized in Table 5. Ethanol production
was further enhanced when a third round of
recycled cells was used in hydrolyzate fermentation
(batch VIII). Ethanol production may have also been
in¯uenced by the density of recycled cells. In batch VI
of wood hydrolyzate, ethanol yield was higher with
high density cells (Table 5, P . 0:02), whereas in batch
V, ethanol yield was similar for both cell densities