DNase Agar with Methyl Green Plate

 

What is this medium used for?  Bacteria are identified based largely on what organic compounds they can break down. The range of compounds used depends on the collection of enzymes a species of bacteria can make. DNA is an organic compound that some bacteria can use for carbon and energy. The enzyme capable of breaking down DNA is called DNase. DNase agar with methyl green is a medium that contains a supply of DNA, and thus it allows us to determine the presence of DNase.

 

How is DNase activity determined?  If DNase is made by the bacterium, the DNA in DNase agar will be digested. The medium, which is normally mint green in color, will have clear halos around colonies of bacteria that make DNase.

 

What is the content of this medium?  DNase agar is a nutrient medium with the dye methyl green present. It also contains DNA to serve as the target for the enzyme.

 

How is the test performed?  For information on how to determine the ability of a microbe to use DNA, refer to the Deoxyribonuclease test .