• Bacteria grow on solid media as colonies.

• A colony is defined as a visible mass of microorganisms all originating from a single mother cell.

Colony Morphology

• These characters used to accurately describe the morphology of a bacterial colony:

-Size

-Shape

-Color (also known as pigmentation)

-Texture

-Height (elevation)

-Edge (margin)

• Key features of bacterial colonies are important criteria for their identification.

COLONY CHARACTER ON AGAR PLATE

• Colony shape on agar plates

Rhizoid

Circular Pinpoint

• Margin of bacterial colony

Undulate filamentous

• Elevation of bacterial colony

Umbonate Raised margin

• Size of the bacterial colony

• Small

• Medium

• large

• Texture of bacterial colony

• Dry

• Moist

• Viscid (stick to loop)

• Mucoid (mucus-like)

• Colour of the colonies (pigmentation)

Some bacteria produce pigment when they grow in the medium.

• Opacity of the bacterial colony

• Opaque (not clear)

• Translucent (clear)

• Iridescent(shine)

COLONY CHARACTER ON AGAR SLANT

• Growth on agar slants

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