270 
Journal of Agricultural Research 
Vol. XXX, No. 3 
amino acids and protiens as sources of 
energy, even in the presence of such an 
available carbohydrate as dextrose. 
The development of Bad. fluorescens 
in the alanine medium was very similar 
to its growth upon glycocoll; that is, a 
larger amount of amino acid has been 
decomposed and a much larger amount 
of ammonia has accumulated in the ab¬ 
sence than in the presence of dextrose. 
The changes in reaction were similar to 
those observed with glycocoll. 
In comparing the amounts of am¬ 
monia found in the medium with the 
amount of growth produced by the or¬ 
ganisms upon glycocoll and alanine, as 
substrates, attention should be called 
to the following fact: The Trichoderma 
liberated, in the case of glycocoll, 24.28 
mg. nitrogen as ammonia for 50 mg. of 
mycelium synthesized and, in the case 
of alanine, 21.98 mg. NH 3 —N for 80 
mg. of mycelium; the Actinomyces lib¬ 
erated, in the case of glycocoll, 30.46 
mg. of NH 3 —N for 59 mg. of mycelium 
and, in the case of alanine, 39.17 mg. 
NH 3 —N for 126 mg. of mycelium. 
This difference is due not to the more 
rapid decomposition of the glycocoll 
(just the reverse is true), but to the fact 
that the C:N ratio is smaller, in the 
case of glycocoll than in the case of 
alanine; the organisms will find more 
available energy in the latter and will, 
therefore, assimilate more of the nitro¬ 
gen and leave a smaller amount of 
waste as ammonia. 
DECOMPOSITION OF PHENYLALANINE 
The chemical formula for phenylala¬ 
nine is QH5.CH2.CH (NH 2 ).COOH; 
this amino acid contains 8.49 per cent 
nitrogen, 65.5 per cent total carbon and 
about 22 per cent carbon, outside of 
the benzol ring. The Zygorhynchus and 
Actinomyces decomposed only a small 
amount of the phenylalanine (Table 
III); the color of the medium soon be¬ 
came reddish and the odor distinctly 
aromatic. It is therefore possible that 
the organism is unable to utilize the 
various products formed from the de¬ 
composition of the phenylalanine, con¬ 
taining the benzol group; their rapid 
accumulation, especially in the absence 
of dextrose, may soon stop the further 
development of the organism. The 
Trichoderma, however, used up, in 6 
days, 37.6 per cent of the phenylalanine 
in the absence of dextrose and 56.4 per 
cent in the presence of dextrose. If the 
efficiency of the organism to assimilate 
carbon is as great with phenylalanine 
as with the other amino acids—40 per 
cent—we could conclude that the 
Trichoderma attacked also the benzol 
group; 131 mg. of dry mycelium con¬ 
tains about 60 mg. C, which would 
indicate about 150 mg. of original car¬ 
bon decomposed; 37.6 per cent of the 
phenylalanine which was decomposed 
in the medium (or 338 mg. of phenyl¬ 
alanine) contained about 220 mg. of 
total carbon and only about 75 mg. of 
the carbon outside of the ring. 
The same is true of the cultures con¬ 
taining the dextrose. All the nitrogen 
of the amino acid decomposed was re¬ 
covered as ammonia and in the 
mycelium.. 
Of the two bacteria, B. cereus made 
no growth at all, while Bad. fluorescens 
decomposed the phenylalanine very 
rapidly, over 55 per cent in 7 days, in 
the absence of dextrose, thus showing 
Table III .—The chemistry of decomposition of 0.9 per cent phenylalanine by 
microorganisms , in the presence and absence of dextrose 
Total N in 
100 c. c. 
NHj-N in 
100 c. c. 
Dextrose in 
100 c. c. 
Dry growth 
Organisms used 
Dex- 
* trose 
Age 
of cul¬ 
ture 
Found 
De¬ 
crease 
from 
con¬ 
trol 
Found 
De¬ 
crease 
from 
con¬ 
trol 
NHs-N 
in 100 
c. c. 
Found 
Util¬ 
ized 
Weight 
Nitro¬ 
gen 
con¬ 
tent 
PH 
Control*_ 
Per cent 
None 
Days 
Mg. 
79.80 
Mg. 
Mg. 
73.96 
Mg. 
Mg. 
Tr. 
Mg. 
Mg. 
Mg. 
Mg. 
7.1 
Do. 
2 
79.80 
73.96 
Tr. 
1,700 
6.5 
Zygorhynchus . 
Do. 
None 
7 
77.90 
1.90 
66.36 
7.60 
8.56 
35 
2.4 
7.7 
2 
7 
66.10 
13.70 
61.08 
12.88 
2.98 
370 
1,330 
272 
14.00 
5.2 
Trichoderma— 
None 
6 
70.00 
9.80 
46.16 
27.80 
17.94 
131 
9.78 
7.8 
Do. 
2 
6 
39.20 
40.60 
32.20 
41.76 
4.22 
325 
1,375 
654 
37.12 
6.0 
Actinomyces..* 
Do. 
None 
26 
30 
2.5 
7.8 
2 
26 
1,640 
60 
42 
2.2 
6.2 
Bact. fluor¬ 
None 
7 
32.56 
41.40 
25.40 
8.1 
escens. 
Do. 
2 
7 
52.60 
21.36 
4.86 
760 
940 
4.4 
