Figure 17.8 Aggregates of
immobilised Teichaxinella morchella
after 19 days of cultivation
(magnification 400 ×)
fed and aerated in bioreactors. Initial experiments were done in spinner flasks.
Proliferation of sponge cells into micro-colonies could be observed in the gel beads as
well.
PERSPECTIVES
Primmorphs and immobilisation of axenic dissociated sponge cells could be a major
breakthrough in sponge-cell culture research. Cell-cell contacts are an essential
prerequisite for growth of sponges. Both methods described above have the advantage
that cell-cell contacts are maintained in axenic sponge-cell cultures. In the case of
primmorphs, cells re-aggregate and in the case of immobilised sponge cells, the cells are
stimulated to divide by growth factors and once small aggregates have been formed
growth can continue.
So far only initial growth has been shown for both systems. Long term growth needs
to be studied. How growth proceeds is not known at the present time. It is possible that
micro-colonies develop further in the same fashion as in the case of immobilised
microorganisms, and diffusion limitation across the biocatalyst particles will occur. On
the other hand the primmorphs or immobilised sponge cells might be able to differentiate
Multiphase bioreactor design 522