Journal article
Glucose metabolism in Lactococcus lactis MG1363 under different aeration conditions: Requirement of acetate to sustain growth under microaerobic conditions
Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation with air was used as the reference).
The maximum specific growth rate was high (0.78 to 0.91 h(-1)) under all aeration conditions but decreased with increasing aeration, and more than 90% of the glucose was converted to lactate. However, a shift in by-product formation was observed. Increasing aeration resulted in acetate, CO2, and acetoin replacing formate and ethanol as end products.
Under microaerobic conditions, growth came to a gradual halt, although more than 60% of the glucose was still left. A decline in growth was not observed during microaerobic cultivation when acetate was added to the medium. We hypothesize that the decline in growth was due to a lack of acetyl coenzyme A (acetyl-CoA) needed for fatty acid synthesis since acetyl-CoA can be synthesized from acetate by means of acetate kinase and phosphotransacetylase activities.
Language: | English |
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Publisher: | American Society for Microbiology |
Year: | 2003 |
Pages: | 3462-3468 |
ISSN: | 10985336 and 00992240 |
Types: | Journal article |
DOI: | 10.1128/AEM.69.6.3462-3468.2003 |
ORCIDs: | Villadsen, John |