# 105: GLUCONOBACTER OXYDANS MEDIUM


## Main sol. 105

100	g	Glucose	
10	g	Yeast extract	
20	g	CaCO3	
1000	ml	Distilled water	
15	g/l	Agar, for solid medium	

1. Adjust pH to 6.8.
2. 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.