# 1320: HALF STRENGTH R2A MEDIUM IN 75% SEAWATER


## Main sol. 1320

1000	ml	**Main sol. 830**, prepare half strength medium with 75 % seawater	

1. Refer to the composition of DSMZ medium 830 and either make up the medium in 2 litres of 75% seawater or use half of the amounts of the components specified and make up the medium in 1 litre of 75% seawater. Liquid medium can be prepared by leaving out the agar.


## Main sol. 830

0.5	g	Yeast extract	
0.5	g	Proteose peptone (Difco no. 3)	
0.5	g	Casamino acids	
0.5	g	Glucose	
0.5	g	Starch (soluble)	
0.3	g	Na-pyruvate	
0.3	g	K2HPO4	
0.05	g	MgSO4 x 7 H2O	
15	g	Agar	
1000	ml	Distilled water	

1. Final pH 7.2; adjust with crystalline K2HPO4 or KH2PO4 before adding agar. Add agar, heat medium to boiling to dissolve agar, and autoclave for 15 min at 121°C.