Anaerobic growth of Corynebacterium glutamicum via mixed-acid fermentation.
Corynebacterium glutamicum, a model organism in microbial biotechnology, is known to metabolize glucose under oxygen-deprived conditions to l-lactate, succinate, and acetate without significant growth. This property is exploited for efficient production of lactate and succinate. Our detailed analysis revealed that marginal growth takes place under anaerobic conditions with glucose, fructose, sucrose, or ribose as a carbon and energy source but not with gluconate, pyruvate, lactate, propionate, or acetate. Supplementation of glucose minimal medium with tryptone strongly enhanced growth up to a final optical density at 600 nm (OD600) of 12, whereas tryptone alone did not allow growth. Amino acids with a high ATP demand for biosynthesis and amino acids of the glutamate family were particularly important for growth stimulation, indicating ATP limitation and a restricted carbon flux into the oxidative tricarboxylic acid cycle toward 2-oxoglutarate. Anaerobic cultivation in a bioreactor with constant nitrogen flushing disclosed that CO2 is required to achieve maximal growth and that the pH tolerance is reduced compared to that under aerobic conditions, reflecting a decreased capability for pH homeostasis. Continued growth under anaerobic conditions indicated the absence of an oxygen-requiring reaction that is essential for biomass formation. The results provide an improved understanding of the physiology of C. glutamicum under anaerobic conditions.
IBG-1 Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany.
Andrea
A
Michel
IBG-1 Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany.
Abigail
A
Koch-Koerfges
IBG-1 Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany.
Karin
K
Krumbach
IBG-1 Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany.
Melanie
M
Brocker
IBG-1 Biotechnology, Institute of Bio- and Geosciences, Forschungszentrum Jülich, Jülich, Germany m.bott@fz-juelich.de.
Michael
http://orcid.org/0000-0002-4701-8254
M
Bott
D000332:Aerobiosis; D000693:Anaerobiosis; D019149:Bioreactors; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000254:growth & development* / Q000378:metabolism*; D004734:Energy Metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000378:metabolism
D002264:Carboxylic Acids; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen