similar behavior of the latter type has been reported in
literature. In calcium-alginate entrapped yeast cells, both
glucose uptake and ethanol production were increased [5].
In addition, Hilge–Rotmann and Rehm [17] observed an
increase in hexokinase activity in gel-entrapped cells compared
to freely suspended cells. They noticed also that this
increase was less pronounced at very low cell densities in
the gel, indicating that high cell density, a condition that is
met with DEAE-cellulose immobilized cells, may be responsible
for this increase in glucose flux, and decrease in
cell yield [17]. In a packed bed reactor, lower cell yields are
of significant importance since biomass formation shortens
production periods due to pressure increase and blockage of
flow.