THE BIOCHEMISTRY OF STREPTOCOCCUS 

 HEMOLYTICUS 



LAURENCE F. FOSTER 

 From the Department of Pathology and Bacteriology, University of California 



Received for publication August 15, 1920 

 I. THE ACIDS PRODUCED BY STREPTOCOCCUS HEMOLYTICUS^ 



The cessation of activity in a glucose broth culture of Strepto- 

 coccus hemolyticus comes when a fairly constant point of hydro- 

 gen-ion concentration is reached. This change is caused by a 

 fermentation of the medium with a resultant formation of acid 

 substances. The present section of this paper has to do with 

 the chemical nature of these acid products. 



A review of the literature reveals the fact that scant attention 

 has been paid to the biochemistry of bacterial fermentations. 

 Emmerling (1896), in 1896, carried out determinations of acids 

 obtained from the putrefaction of certain proteins through the 

 action of Proteus and Staphylococcus pyogenes. Tissier and 

 Martelly (1902) in a study of the putrefaction of meat found that 

 Streptococcus pyogenes could only split natural proteins after the 

 latter had been peptonized. The same organism rapidly attacked 

 glucose forming, chiefly, lactic acid. Clostridium welchii and C. 

 sporogenes were found to produce acid and alkaline substances si- 

 multaneously. Later work by Wolf and Telfer (1917) upon these 

 last-mentioned organisms has shown that a large proportion of the 

 acid formed in their fermentations is volatile in character. The 

 method of Dyer (1916) was employed by these investigators in 

 determining the volatile acids. Forty per cent of the total acid 

 produced by the organisms mentioned proved to be non-volatile. 

 The exact chemical nature of this fraction was not determined. 



' Miss Bernice Rhodes rendered valuable assistance in carrying out the experi- 

 mental work described in this section of the paper. 



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