The immobilization of enzymes and yeast cells is a key factor for establishing a continuous process of
cellulosic ethanol production, which can combine the benefits of a separated hydrolysis and fermentation
process and a simultaneous saccharification and fermentation process. This paper investigates the
use of cellulase enzyme and yeast cell immobilization under a flow regime of ethanol production from
soluble substrates such as cellobiose and carboxymethyl cellulose. The immobilization was achieved by
incubating enzymes and yeast cells on polystyrene surfaces which had been treated by nitrogen ion
implantation. The saccharification by immobilized enzymes and the fermentation by immobilized yeast
cells were conducted in two separate vessels connected by a pump. During the experiments, glucose
concentrations were always maintained at low levels which potentially reduce product inhibition effects
on the enzymes. Covalent immobilization of enzymes and yeast cells on the plasma treated polymer
reduces loss by shear flow induced detachment. The potential for continuous flow production of ethanol
and the influence of daughter yeast cells in the circulating flow on the immobilized enzyme activity are
discussed.