No overgrown of felt like mold mycelium layer was seen in co-immobilized gel beads. The results showed that A. oryzae or M. purpureus mainly grew on the oxygen-rich surface area of gel beads, whereas S. cerevisiae grew mainly in the oxygen-deficient inner part and to a lesser extent also on
the oxygen-rich surface area. Kurosawa et al. also described that
microorganisms in gel beads during ethanol fermentation formed
a similar pattern as described above