PRODUCTION OF AXTIinoTICS 



37 



Table 12 



Strain sclccHoti hi/ raridus methuds of trealiiient ( Alikhaniaii, 19591)) 



('/ al. (H).')!)), Alikhaniaii d al. (U).")9), and 

 Mindlin and Alikhaniaii (l'.)58). 



Improvemcnl of Media and 

 Cidlural Conditions 



During the de\elopment of a process for 

 the production of a given antibiotic, the 

 work on strain selection and the study of 

 media and cultural conditions go hand in 

 hand. 



In improving media, the following nu- 

 trients must be investigated: (1) sources of 

 carbon, (2) sources of nitrogen, (.3) mineral 

 sources, and (4) growth-promoting sub- 

 stances. 



Several important factors are known to 

 influence the growth of the antibiotic-pro- 

 ducing organism: (1) temperature, (2) initial 

 pH and control of pH during growth, (3) 

 aeration, and (4) agitation. 



The medium used to grow the inoculum, 

 the age of the inoculum, and its size will 

 markedly influence the jjroduction of anti- 

 biotics. 



Kffeel of Composition of Medium on 

 Antibiotic Production 



The composition of the medium has a 

 highly important eflect upon the growth and 

 metabolic activities of actinomycetes, and 

 upon the production of antibiotics. Both the 

 (luantitative yield of speciflc antibiotics and 

 their chemical structure are greatly influ- 

 enced by the nature of the nutrients (carbon 

 and nitrogen sources), their concentrations, 

 and the presence of specific salts. 



When streptomycin was first produced by 

 freshly isolated strains of »S'. griseus (Schatz, 

 Bugie, and Waksman, 1944), the maximal 

 yield of the antil^iotic was 100 to 200 /xg per 

 ml. In recent years, this yield has been in- 

 creased to between 5 and 10 mg per ml. Al- 

 though the proper strain development had a 

 great deal to do with this phenomenal in- 

 crease, the selection of suitable media and 

 optimal conditions of growth w(n-e also 

 la rgely responsi l)le . 



The addition of basic amino acids (argi- 



