GLUCONOBACTER OXYDANS MEDIUM

Glucose                                  100.0 g

Yeast extract                            10.0 g

CaCO3                                     20.0 g 

Distilled water                       1000.0 ml

Adjust pH to 6.8

Add  agar 15 g/l for solid media.

20 g calcium carbonate in the medium serves as a buffer. The calcium carbonate will settle in agar plates before the agar has set, producing an opaque layer in the bottom. As the strain grows and acid is produced this will react with the calcium carbonate, causing it to dissolve and form zones of clearing immediately below the colonies. In liquid culture the calcium carbonate also forms a sediment that clears as acid is produced.