Colonies of M. tuberculosis appear in about

→ Generation time : 14-15 hours. → Colonies appear in about 2 weeks (may take upto 8 weeks). → Grows luxuriantly in culture (Eugonic) and addition of 0.5% glycerol improves its growth but it has no effect on M.Bovis, which is dysgonic (Grows sparsely). → Solid medium ⇒ Most widely employed for routine culture is Lowenstein-Jensen (LJ) medium without starch.