The cell wall of Mycobacterium is accountable for its slow growth, being strongly impermeable to nutrients, and for its compact, wrinkled appearance in colony morphology. Most nutrients are hydrophobic such as certain fats and vitamins as well as some form of carbohydrates and proteins. Since the cell wall is hydrophobic, nutrient absorption of Mycobacterium is slow hence growth of the organism is also slow. A wrinkled colony appearance is also characteristic of microorganisms with hydrophobic cell walls.
On the other hand, while Mycobacterium is an aerobic organism; the hydrophobicity of the cell wall do not account for this characteristic of the organism.