lMl^■sl()I,()(;^■ 



129 



moiiiuni ion as tlic sole source of cai'lxtii, 

 uitrogcMi, and cniM-iiy. 



(Mianjics in reaction as a result ol' <i;i-o\\tli 

 of \arious act inoniycetes depend hotli on the 

 oi\<ianisni and on the composition of the 

 nuHlium (\\'aksnian and JolYe). I'l-otein-rich 

 media give an alkaline reaction e\-en in the 

 presence of sugars, largely because of am- 

 monia accumulation. When actinomycetes 

 are grown on media containing sugars and 

 ammonium sulfate as a source of nitrogen, 

 the media usually turn acid as a result of the 

 consumption of the ammonia and tlie ac- 

 cunuilation of sulfat(\ Mc^lia containing 

 sugars and sodium nitrate may first turn 

 acid, then alkaline, as a result of the con- 

 sumption of the nitrate and the accumula- 

 tion of the sodium ion in the medium. The 

 great majority of actinomycetes prefer a 

 neutral or a shghtly alkaUne reaction for 

 their growth, ^'er3^ few prefer an acid reac- 

 tion. 



Oxygen Consumption by Actinomycetes 



The oxygen uptake by *S'. laveridulae, with 

 glucose and glycerol as sources of carbon, 

 was found to be 60 and 45 per cent, respec- 

 tively. The incomplete oxidation Avas due to 

 assimilation of some of the products for cell 

 synthesis and to the formation of incom- 

 pletely oxidized products, such as lactic 

 acid. 



Shaking and motion of cultures of actino- 

 nu'cetes usually do not affect all forms alike. 

 The effect of motion has been compared to 

 that of temperature: in both cases, energy 

 is brought from the outside to the living 

 cells; this exerts a favorable action up to a 

 certain limit; above that limit, the results 

 may become unfavorable. Shaking the cul- 

 ture brings about an exchange in the at- 

 mospheric gases, the organism obtaining a 

 continuously fresh supply of oxygen. This 

 affects favorably its growth and activities. 



The type of growth produced by an 

 actinomvcete in sul^merged culture varies 



NH.-N 



MG/IOML 



23496 789 10 n 



DAYS OF FERMENTATION 



Figure 61. Fermentation characteri.stics of S. 

 griseus (Reproduced from: Woodruff, H. B. and 

 Rviger, M. J. Bacteriol. 56: 316, 1948). 



greatly from stationary growth. In place of 

 the ordinary mycelial mat of stationarj^ 

 growth, the growth in sulimerged culture is 

 limited to flakes or to bead-like masses or 

 pellets which may fill the Avhole container. 

 The physiology of the organism may also be 

 markedly affected, one type of antibiotic 

 being produced, for example, in stationary 

 cultures and another type in submerged. 



Pine and Howell studied 11 strains of the 

 .4. Israeli and A. naeslundii types. These 

 strains were found to require CO 2 for ana- 

 erobic growth. Some of them Avere found to 

 be obligate anaerobes to microaerophiles, 

 others weve facultative anaerobes. Further 

 studies of the respiration of Streptomyces 

 species have been carried out by Cochrane 

 rt al., Kemp and Sayles and many others. 



