CULTURE MEDIA 25 



MEDIA FOR NITRATE-REDUCING AND DENITRIFYING BACTERIA 



Medium 55 



AsPARAGiN Nitrate-citrate (Giltay's) Solution 



(a) Potassium nitrate (KNO3) 1.0 gm. 



Asparagin (C4H8N2O3H2O) 1.0 gm.^ 



Distilled water 250. cc. J 



(h) Citric acid (CeHgOT-HsO) 5.0 gm. ^ 



or neutral sodium citrate 8.5 gm.y 



Monopotassium phosphate (KH2PO4) 1.0 gm.— , 



Magnesium sulphate (MgS04-7H20) 1.0 gm.-^^ 



Calcium chloride (CaCl2-6H20) 0.2 gm. • 



Ferric chloride (FeCla-OHoO) trace ~. 



Distilled water 250 . cc. - 



Neutralize the citric acid solution with a 10 per cent solution 

 of sodium or potassium hydroxide, using phenolphthalein as an 

 indicator. Mix the two solutions and add sufficient water to 

 make 1000.0 cubic centimeters. If the asparagin and potassium 

 nitrate are dissolved along with the other salts, a decomposition 

 may occur. This is marked by a browning of the liquid due 

 to the presence of nitrous acid. 



For a solid medium add 15 grams of agar to 1 liter. 



Medium 56 



Potassium Nitrate-glucose Solution 



Potassium nitrate (KNO3) 1.0 gm. 



Dipotassium phosphate (K2HPO4) 0.5 gm. 



Calcium chloride (CaCl2-6H20) 0.5 gm. 



Glucose 10.0 gm. 



Distilled water 1,000.0 cc. 



Medium 57 



Potassium Nitrate-ethyl alcohol Solution^ 



Dipotassium phosphate (K2HPO4) 0.5 gm. 



Potassium nitrate (KNO3) 10.0 gm. 



Ethyl alcohol (C2H5OH) 5.0 cc. 



Tap water 1,000 . cc. 



1 Beijerinck, M. W., Centr. Bakt., II Abt., 25: 35, 1910. 



