Chapter V — 81 — Metabolism 



carbon, and liberates considerable waste nitrogen in tlie form of ammonia 

 (Tables 9, 10). 



Most media for actinomycetes contain a certain amount of carbo- 

 hydrate. This is included to enable the organisms to make more ex- 

 tensive growth and to serve as a buffer, since with proteins and protein- 

 derivatives as die onlv source of carbon, ammonia accumulates so 



Table 9: Decomposition of different amino acids by microorganisms (472): — 

 100 ml medium containing 1 per cent of amino acid 



rapidly as to make the medium too alkaline for further growth of the 

 organism. That the favorable effect of glucose in increasing the growth 

 of actinomycetes in the presence of peptone or protein is due, partly at 

 least, to the neutralizing effect of the ammonia produced from the pep- 

 tone by the acid produced from the glucose was known to some of the 

 early investigators of this group of organisms (323). In the case of ty- 

 rosin utilization by actinomvcetes, glucose had a favorable effect upon 



Table 10: Decomposition of glycine by different microorganisms in presence of glucose (472): — 

 100 ml medium containing 1 per cent glycine and 2 per cent glucose 



Glycine-N Glucose Growth, NHs-N 



Organism decomposed decomposed dry w^eight produced 



the growth of only those organisms that were able to form, from tyrosin, 

 substances that neutralized the acid produced from the sugar. Certain 

 amino acids, like leucine, were utilized by actinomycetes only in the 

 presence of an available carbohydrate. 



Urea can serve only as a source of nitrogen; not of carbon (125, 

 307). Actuallv, urea is produced by certain actinomvcetes from pep- 

 tone (160). 



