DECOMPOSITION OF PROTEINS 



495 



pure cultures of various fungi was found 66 to depend on the type of 

 organism used ; Monilia sitophila reached its maximum in 3 to 4 days, 

 Mucor plumbeus reached it in 6 to 10 days. 



Rate of ammonia formation by microorganisms and methods of deter- 

 mination. In the decomposition of proteins by pure cultures of bacteria 



TABLE 43 



Ammonia formation by soil fungi 



Pen. intricatum. 

 Pen. intricatum. 



Pen. chrysogenum . 

 Pen. chrysogenum 



Asp. fumigatus 

 Asp. fumigatus 



Mucor hiemalis. 

 Mucor hiemalis . 



Rhiz . nigricans . 

 Rhiz. nigricans . 



Zyg. vuilleminii , 

 Zyg. vvilleminii . 



Monilia sitophila . 

 Monilia sitophila . 



Trich. koningi. 

 Trich. koningi. 



SOURCE OF NITROGEN* 



MILLIGRAMS OF NH|N 



* To 100 grams of soil were added 155 mgm. of nitrogen in the form of D. B. 

 Dried blood or of C. S. M. = cottonseed meal. 



or fungi, as well as in the soil itself, the rate of ammonia accumulation 

 is that of an autocatalytic chemical reaction. 67 However, the nature 

 of the protein and the presence of non-nitrogenous organic matter 



66 Waksman, S. A., and Cook, R. C. Incubation studies with soil fungi. 

 Soil Sci., 1: 375-384. 1916. 



87 Miyake, 1916 (p. 375); Waksman, S. A. Studies on proteolytic activities of 

 soil microorganisms with special reference to fungi. 

 1918. 



Jour. Bact., 3: 475^92. 



