The genus, Streptomyces belongs
to the family Streptomycetaceae, a unique family
of the suborder, Streptomycineae. Streptomycetes
grow as mycelia filaments in soil; their mature
colonies may contain two types of mycelia, the
substrate (vegetative) mycelium, and the aerial
mycelium. Each has a different biological role
(Hopwood, 1999). Vegetative mycelia absorb
nutrients and are composed of a dense and
complex network of hyphae usually embedded in
the soil or immobilize substrate. Once the cell
culture becomes nutrient-limited, an aerial
mycelium developed from the surface of the
vegetative mycelium. The role of this type of
mycelium is mainly reproductive; indeed, the
aerial mycelium develops into spore chains at the
matured stage in their life cycle (Hopwood, 1999).
In this study, both, reproductive and aerial
mycelium along with clearly sporulation of some
mesophilic Streptomyces strains is shown in
Figure 4.