272 
Joumal oj Agricultural Research 
Vol. XXX, No. 3 
acid than with the other three acids 
previously studied. This is attribu¬ 
table, on the one hand, to the much 
larger ratio of the carbon to the nitro¬ 
gen in the particular amino acid, and, 
on the other, to the fact that glutamic 
acid is very favorable to respiration, 
resulting in the formation of very 
little volatile acid. Nawiasky (18) 
found that B. proteus will transform, 
in 3 days, 11.67 per cent of the nitro¬ 
gen of glutamic acid to ammonia and, 
in 15 days, 52.97 per cent. The 
amount of ammonia, in comparison 
with the amount of mycelium syn¬ 
thesized is smaller in the case of the 
glutamic acid than in the case of 
glycocoll or alanine, as shown in the 
following summary: 
tion given by Jodidi was that “the 
slower formation of ammonia from 
leucine is to be ascribed to the inert 
paraffin character of the comparatively 
long hydrocarbon chain, etc.” Jodidi 
was correct, however, in respect to 
phenylalanine, which produced even less 
ammonia than the leucine, owing to the 
resistant character of its benzene ring. 
Kelley (11) also brought out the fact 
that the ammonia content of the 
medium is definitely affected by its 
carbon content. The same amount 
of ammonia was formed from casein, 
soybean cake, cottonseed meal and 
linseed meal, when enough starch was 
added to each, so as to have the same 
amount of nitrogenous and nonnitrog- 
enous substances, the carbon-nitrogen 
Amino acid 
C/N 
Organism 
Growth 
NH3-N 
Growth 
NH3-N 
Glycocoll - _ 
1. 7 
Trichoderma_ _ 
Mg. 
50 
Mg. 
24.28 
2.0 
Do 
1. 7 
Actinomyces_ 
59 
30.46 
2.0 
Alanine * _ 
2.57 
Zygorhynchus __ _ 
48 
6. 40 
7.5 
Do 
2. 57 
Trichoderma_ 
80 
21. 98 
3.6 
Do 
2. 57 
A ctinomy ces _ ___ 
126 
39.17 
3.2 
Glutamic acid 
4. 28 
Zygorhynchus. .. _ 
204 
25. 40 
8.0 
Do_ _ _ 
4. 28 
Trichoderma_ 
218 
29.12 
7. 5 
Do - _ 
4. 28 
Actinomyces_ _ 
! 169 
28. 36 
5.9 
Do 
4. 28 
B. fluorescens_ 
! 128 
28.50 
4.5 
1 
The higher the ratio of carbon to 
nitrogen in the amino acid molecule, 
the less is the amount of ammonia pro¬ 
duced per unit of protoplasm syn¬ 
thesized. This is based upon the simple 
principle that ammonia is a waste prod¬ 
uct in the carbon metabolism of an or¬ 
ganism, with proteins or their deriva¬ 
tives as sources of energy; the amount 
of ammonia accumulated in the medi¬ 
um depends upon the growth of the 
organism and particularly upon the 
ratio of the available carbon to the 
available nitrogen in the medium; this 
holds true also when an available car¬ 
bohydrate, like dextrose, is present in 
the medium; when the amount of avail¬ 
able carbon is increased, the amount of 
ammonia accumulation, under the 
same conditions, will be decreased. 
It is interesting to point in this con¬ 
nection to the work of Jodidi (10), 
who found that glycocoll, containing 
18.7 per cent nitrogen, was decom¬ 
posed in the soil and about 80 per 
cent of the nitrogen was transformed 
into ammonia, whereas leucine, with 
10.7 per cent nitrogen, gave only 50 
per cent of its nitrogen as ammonia. 
This is exactly what one might expect 
from the above considerations, since 
the C/N of glycocoll is 1.7 and the 
C/N of leucine is 5.1. The explana- 
ratio actually affecting the ammonia 
formation in soils. 
By comparing the ammonia formed 
by the three groups of organisms— 
the fungi, actinomycetes, and bacteria 
—an increasing amount of ammonia 
is found to be formed per unit of pro¬ 
toplasm synthesized, in order named. 
This holds true in spite of the fact that 
fungi contain the smallest percentage 
of nitrogen, and can be explained only 
by a proper understanding of the 
metabolism of these three groups of 
organisms. The fungi reassimilate the 
largest proportion of carbon; there¬ 
fore they will also reassimilate a pro¬ 
portionately larger amount of nitrogen 
and leave a proportionately smaller 
amount of waste nitrogen as ammonia. 
The actinomycetes, and especially 
the bacteria, which produce a smaller 
amount of growth, use the available 
energy less economically; they assimi¬ 
late less of the nitrogen, waste more of 
the carbon (as CO 2 ), and therefore 
liberate a larger amount of ammonia, 
as shown in the summary taken from 
Table IV (shown on page 273). 
For approximately the same amount 
of ammonia formed, the fungi decom¬ 
posed less amino acid and produced a 
heavier growth than the Actinomyces 
and Bacterium. 
