Spores of the biocontrol agent, Streptomyces
melanosporofaciens EF-76, were entrapped by complex coacervation
in beads composed of a macromolecular complex (MC) of chitosan and
polyphosphate. A proportion of spores entrapped in beads survived the
entrapment procedure as shown by treating spores from chitosan beads
with a dye allowing the differentiation of live and dead cells. The
spore-loaded chitosan beads could be digested by a chitosanase,
suggesting that, once introduced in soil, the beads would be degraded
to release the biocontrol agent. Spore-loaded beads were examined by
optical and scanning electron microscopy because the release of the
biological agent depends on the spore distribution in the chitosan
beads. The microscopic examination revealed that the beads had a porous
surface and contained a network of inner microfibrils. Spores were
entrapped in both the chitosan microfibrils and the bead lacuna.