|Diversity of metabolic shift in response to oxygen deprivation in Corynebacterium glutamicum and its close relatives.
Appl. Microbiol. Biotechnol. 90: 1051-1061. 2011.
S. Yamamoto, M. Sakai, M. Inui and H. Yukawa.
Oxygen-deprived Corynebacterium glutamicum R cells remain metabolically active, producing considerable amounts of
organic acids even when not actively growing. We compared the proficiencies
of C. glutamicum and close relatives grown under aerobic conditions to metabolize glucose
when deprived of oxygen. Eight strains that readily consumed glucose without
cell growth subsequently produced organic acids. Among these, the glucose
consumption rates of the two C. glutamicum strains (>40 mM/h) and Corynebacterium efficiens (>12 mM/h) were an order of magnitude higher than those of the other
five strains. The resultant organic acid yields of these three strains
(>86%) consequently exceeded those of the other five (<60%). This
difference is probably rooted in the comparatively inferior activities
of glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and
malate dehydrogenase observed in the five strains. Moreover, under oxygen
deprivation, phosphoenolpyruvate carboxylase (PEPC) activity of C. efficiens was elevated tenfold, but its lack of fumarase activity meant that no
succinic acid could be produced. The metabolic shift occasioned by addition
of the PEPC substrate sodium bicarbonate resulted in a doubling of the
glucose consumption rate of the two C. glutamicum strains but not that of the other six close relatives.