302 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



Preparation : 



(1) Dissolve 2, 3, 4 and 5 in 1 by boiling 

 3 minutes. Make up the loss of 

 water. 



(2) Adjust to pH = 7.4. 



(3) Tube in 5 cc. quantities. 

 Sterilization: Heat in the autoclave at 20 



pounds pressure for 30 minutes. 



Use: To study the relation of substances 

 formed by B. coli to the growth of yeast. 

 The author reported that this medium 

 did not support the continued growth of 

 yeast. The addition of aqueous extracts 

 of autolized yeast and grated carrot to 

 the medium in high dilution permitted the 

 growth of yeast, but caused no increased 

 growth of B. coli. The filtrate of the 

 synthetic medium on which B. coli had 

 been grown for 68 generations, per- 

 mitted the continued growth of yeast. 



Reference: Robertson (1924 p. 396). 



981. Kister's Yeast Digest 



Constituents: 



1. Water. 



2. Yeast. 

 Preparation : 



(1) Dissolve the proteins and extractives 

 from dry yeast by means of water. 



(2) Evaporate or condense the extract a 

 thick syrupy mass. This composes 

 the yeast extract. 



(3) To obtain a yeast peptone subject the 

 yeast extract to super-heated steam 

 for some time (exact time not spec- 

 ified). 



(4) Change the hydrolysed mass into a 

 light yellow powder. This gives you 

 a yeast peptone — soluble in water. 



Sterilization: Material required no further 

 sterilization. 



Use: In the preparation of yeast media, 

 the yeast extract replaces the meat 

 extract and the yeast peptone 'replaces 

 the Witte or commercial peptone. 



Variants: Kister reported that Yeast pep- 

 tone may also be prepared by an acid 

 hydrolysis under pressure or by a pepsin 

 hydrolysis, in an incubator, of the protein 

 of the yeast after the separation of the 

 extractive materials. Exact method not 

 given. 



Reference: Kister (1921-22 p. 478). 



982. Kligler's Yeast Autolysate Solution 



Constituents: 



1. Water 1000.0 cc. 



2. Yeast 200.0 



3. NaHjPOi 2,0 g. 



Preparation : 



(1) Suspend 200.0 g. of drained or centri- 

 fuged brewers yeast in a liter of water. 



(2) Add 2.0 g. NaH2P04. 



(3) Add N/1 NaOH to obtain pH = 6.1. 



(4) Add 5.0 cc. chloroform. 



(3) Shake well— incubate at 37° for 2 

 days, shaking occasionally. 



(6) After incubation, adjust to pH = 7.4 

 and heat in water bath or Arnold for 

 30 minutes. 



(7) Filter thru paper. 



(8) Tube. 



Sterilization: Sterilize in the autoclave. 

 Use: Substitute for meat or meat infusion 



media for the cultivation of colon-typhoid 



group and others. 

 References: Kligler (1919 pp. 183-186), 



Harvey (1921-22 p. 120). 



983. Jotten's Yeast Autolysate Solution 



Constituents : 



1. Water. 



2. Yeast (brewer's) 10,000.0 g, 



3. NaCl 0.8 % 



4. KNO3 0.01% 



Preparation : 



(1) Wash 10,000.0 g. of brewers yeast 

 twice with 20 liters of water. Use a 

 large centrifuge if possible. 



(2) Add N/1 NaOH or (NH 4)200 3 until 

 the whole mass has turned brown. 

 Shake thoroly when adding NaOH or 

 (NH 4)200 3. 



(3) Allow to stand for 30 to 60 minutes. 

 This dissolves some of the im- 

 purities. 



(4) Add fresh cold water to (2). This 

 causes the yeast to separate in flakes. 

 (Amount of water not given.) 



(5) Allow the yeast to settle for several 

 hours. 



(6) Remove the water from the yeast. 



(7) Add fresh water (amount not given). 



(8) Distribute in 5 liter flasks, and place 

 at 45° for 48 hours. 



(9) Pour off the brown liquid. 



