Jl. Boiardi, METABOLIC COST OF NITROGEN INCORPORATION BY N-2-FIXING AZOTOBACTER-VINELANDII IS EFFECTED BY THE CULTURE PH, Biotechnology letters, 16(11), 1994, pp. 1195-1198
N-2-fixing continuous cultures of Azotobacter vinelandii ATCC 9046 wer
e carried out under various dissolved oxygen tensions (2, 25 and 50% a
ir saturation) and, for each of these oxygen concentrations, the cultu
re pH was controlled at 6.2 and 7.4. The culture pH exerted a profound
influence on the specific consumption rates of glucose and oxygen and
an the growth yields. Parallely, the total metabolic cost far N-incor
poration was affected: for incorporating a given amount of N an extra
glucose consumption of more than 70% took place when the culture pH wa
s changed from 7.4 to 6.2. This effect was observed when the dissolved
oxygen tension in the cultures was 25 or 50% but was lass pronounced
when it was 2% air saturation.