Apr, at, 1923 
Protein Synthesis by Azotobacter 
269 
The average yield of the three cultures for four consecutive days 
was as follows: 12.31 per cent, 28,81 per cent, 24,10 per cent, and 23.14 
per cent of the dextrose originally present in the medium. 
The effect of different quantities of dextrose upon nitrogen fixation 
and the )deld was determined for media containing 0.5 per cent and 
i.o per cent dextrose. Flasks containing 250 cc. of medium were seeded 
with Azotobacter and aerated for four days at 30^ C. Total nitrogen 
and yield determinations were made at the end of the incubation period. 
The results for the two cultures studied are recorded in Table III. 
Tabi.Q III .—Effect of varying quantities of dextrose upon yield and nitrogen fixation 
by Azotobacter 
Culture No. 
0.5 per cent dextrose. 
I per cent dextrose. 
Weight. 
Yield. 
Nitrogen 
per 100 cc. 
Weight. 
Yield. 
Nitrogen 
per 100 cc. 
19. 
232. 
Average.... 
Gm. 
[ 0.0413 
1 -0437 
f . 0322 
1 -0357 
Per cent, 
} . 
} 13-58 
Mgm. 
9. 88 
7 - 57 
Gm. 
( 0. 1014 
1 *1153 
/ -1143 
\ . 1282 
Per cent, 
1 21. 66 
1 24.24 
Mgm, 
16. 38 
16. 65 
15- 29 
8. 72 
32 . 
16.57 
The largest yield for the quantity of dextrose used was obtained from 
the medium containing i per cent dextrose. The average yield for the 
two cultures was 22.95 per cent for this medium as compared with 
15.29 per cent for the cultures cultivated in the 0.5 per cent dextrose 
medium. In the i.o per cent solution the cultures fixed on an average 
16.57 mgm. of nitrogen per gram of sugar; and in the media containing 
0.5 per cent dextrose, an average of 8.72 mgm. of nitrogen per half 
gram of dextrose. In other words, the rate of fixation was practically 
the same in both solutions. 
A similar experiment was made with media containing approximately 
0.5 per cent, 1.0 per cent, and 1.5 per cent of dextrose, respectively. 
The yield with each percentage of dextrose used, the quantity of nitro¬ 
gen fixed, and the rate of dextrose fermentation were determined every 
two days for a period of six days. The cultures were vigorously aerated 
at 30® C. The dextrose content of the control media by analysis was 
0.60 per cent, i.i per cent, and 1.5 per cent, respectively. The results 
are summarized in Table IV. The percentage of yield is based upon 
the quantity of dextrose originally present in the media. 
TabliS IV .—Comparison of various quantities of dextrose in culture No. ig upon yields 
nitrogen fixation^ and dextrose fermentation. 
0,6 per cent dextrose. 
I.I per cent dextrose. 
1.5 per cent dextrose. 
3 days. 
4 days. 
6 days. 
a days. 
4 days. 
6 days. 
a days. 
4 days. 
6 days. 
Weifirht . 
/o. 0354 
\ . 0328 
11*3 
. 20 
6-37 
0. 0399 
0. 0692 
. 0669 
22. 6 
0 
9. 70 
0. 0766 
•0574 
12 . I 
.68 
7. 41 
0. 1506 
. 1280 
^^ 5-3 
Trace 
17. 29 
0. 1245 
•1317 
23-3 
0 
18. 72 
0. 1190 
•1354 
x6.9 
.98 
9.1 
0. 2383 
•2713 
^ 33*9 
Trace 
17.68 
0. 2036 
. 1928 
27. 0 
0 
26. 0 
Yield (per cent)... 
Pextrose (gm,).... 
Nitrogen (mgm.). . 
Trace 
9 * 75 
30617 - 23-—7 
