Created by
Paul A. Gulig, Ph.D.
Department of Molecular Genetics and Microbiology
with assistance from
David Brumbaugh
What is the significance of the two colony types?
A. Type 1 is lactose-positive, and type 2 is lactose-negative.
No, the red color shows that acid was produced from lactose, meaning the bacteria could ustilize lactose as a carbon source.