108 MANUAL OF MICROBIOLOGICAL METHODS 



MEDIA 



Formulas employed by the American Type Culture Collection: 



1. Ayers & Johnson Agar 



Stock culture agar (Difco) 50 g 



Distilled water 1,000 ml 



pH 7.4 



2. Acetobacter Agar (Glucose) 



Autolyzed yeast 10 g 



CaCOs 10 g 



Agar 15 g 



Distilled water 1,000 ml 



Heat to 100°C, and add 



Glucose 3 g 



In tubing, the CaCOs should be distributed evenly between tubes. After auto- 

 claving, the tubes should be shaken, then cooled quickly and slanted so as to keep the 

 CaCOs in suspension. 



3. Acetobacter Agar with Liver Extract 



Liver extract 100 ml 



Tryptone 5 g 



Agar 20 g 



Distilled water 900 ml 



Heat to 100°C, and add 



Glucose 20 g 



CaCOa 10 g 



Observe precautions as in formula 2 to keep CaCOs evenly suspended. 



4. Acetobacter Agar (Mannitol) 



Yeast extract 5 g 



Peptone 3 g 



Agar 15 g 



Distilled water 1,000 ml 



Heat to 100°C, adjust pH to 7.4, and add 



Mannitol 25 g 



6. Azotobacter Agar (Glucose) 



K2HPO, 1.0 g 



MgS04 0.2 g 



NaCl 0.2 g 



FeS04 Trace 



Agar 15 g 



Soil extract 100 ml 



Tap water 900 ml 



Dissolve, adjust pH to 7.6, and autoclave. Add 1 ml of sterile 10 per cent glucose 

 to each tube for use. To prepare soil extract place 500 g of air-dry field soil in 1,300 

 ml of 0.1 per cent Na2C0a, autoclave for 1 hr, filter through paper, and make up vol- 

 ume to 1,000 ml. 



