CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



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(10) Add water to the sediment and 

 centrifuge. 



(11) Remove the supernatant liquid of 

 (10) and add to the liquid obtained 

 in (8). This finally leaves about 35 

 to 40 liters of extract. 



(12) Boil for 90 minutes in the steamer 

 and make slightly alkaline to litmus. 



(13) Filter thru paper or cotton. 



(14) Add 8.0 g. NaCl, 0.1 g. KNO3 and 

 0.2 g. NasCOg per liter. 



Sterilization: Sterilize in the steamer on 

 each of 3 successive days. 



Use: Meat extract substitute in the prepa- 

 ration of general culture media. 



Variants : 



(a) The author evaporated (1) to a quick 

 mass, similar to meat extract, using a 

 "Faust-Heim" evaporating oven. 



(b) Klimmer prepared the medium as 

 follows: 



(1) Wash 10,000.0 g. of bottom beer 

 yeast with 20 liters of water, twice, 

 using the centrifuge if possible. 



(2) Add about 1.5 cc. normal NaOH 

 or (NH 4)200 3 to the residue in 

 thin stream, stirring constantly. 

 The liquid becomes dark brown. 



(3) Add cold tap water after 30 to 60 

 minutes. 



(4) Allow to settle and decant the 

 yeast water. 



(5) Stir the yeast mass with water. 



(6) Distribute in 5 liter flasks and 

 incubate at 45°C. for two days. 



(7) Pour off the brown colored liquid. 



(8) Thoroly wash the residue with 

 water, and centrifuge out the 

 residue. 



(9) Mix the liquid from (7) and (8). 

 Total volume 30 to 40 liters. 



(10) Boil for one hour in the steamer. 



(11) Filter thru cotton or paper. 



(12) Neutralize to litmus. 



(13) Add 0.8% NaCl, 0.01% KNO3 and 

 0.02% Na2C03 to (12). 



(14) Sterilize on each of three succes- 

 sive days. 

 (15) The liquid from (9) may be evap- 

 orated to a thick brown paste, 

 and using 15.0 g. per liter to pre- 

 pare the medium. 

 Klimmer reported that the medium 

 might be used instead of ordinary 

 nutrient bouillon and give very good 



results. It might also be used as a 

 basis for the preparation of special 

 media. For the enrichment of 

 cholera allow the autolysis to con- 

 tinue for 3 days instead of 2 as indi- 

 cated in step (6). 

 Reference: Jotten (1920 p. 359), Klimmer 

 (1923 p. 171). 



984. Abt and Blanc's Yeast Autolysate 

 Solution 



Constituents: 



1. Water. 



2. NaCl (0.9%). 



3. Yeast (Brewers). 

 Preparation : 



(1) Wash yeast in water and decant after 

 settling. Repeat this several times. 



(2) Dry the yeast. 



(3) Prepare a physiological salt solu- 

 tion containing 9.0 g. NaCl per 

 1000.0 g. water. 



(4) Add 8 to 10 parts of dry washed 

 yeast to each 100.0 cc. of (3). 



(5) Incubate at 48 to 50° for 24 to 36 

 hours. 



(6) Add two volumes of water to (5). 



(7) Heat to boiling. 



(8) Filter. 



(9) Add soda to neutralize to phenol- 

 phthalein, or make slightly alkaline. 



(10) Heat for 15 minutes at 115°C. 



(11) Filter. 



(12) Evaporate 10.0 cc. of the filtrate to 

 dryness to determine the dry ma- 

 terial. Calculate the dry material 

 in 100.0 cc. 



(13) Dilute (11) so as to have 2.1 or even 

 0.5 parts of dry material per 100.0 cc. 



(14) Distribute as desired. 

 Sterilization: Sterilize at 110° for 15 



minutes. 



Use: General culture medium for colon- 

 typhoid group, parasitic and saprophytic 

 forms and others. 



Variants: Robertson and Davis prepared 

 a similar medium as follows: 



(1) Grow yeast on dextrose agar slants. 



(2) Suspend in sterile distilled water, 

 throw down in centrifuge and wash 

 in sterile distilled water 3 times. 



(3) Kill yeast by heating at 70 °C. for 

 10 minutes. (The suspension con- 

 tained about 500,000 per cc.) 



