Metabolic flux in glucose/citrate co-fermentation by lactic acid bacteria as measured by isotopic ratio analysis.
The flux of carbon into lactic acid, diacetyl and acetoin during the co-metabolism of glucose and citrate by Lactococcus lactis subsp. lactis biovar. diacetylactis has been determined using natural abundance isotopic ratio analysis. During fermentation in the conditions used (glucose, 27.8 mM; citric acid, 13.9 mM; initial pH 6.2-6.4, anaerobic) it is shown that approximately 65% of the carbon source used for the aroma compounds is derived from the carbohydrate. Equally, citrate contributes approximately 30% of the carbon recovered in lactic acid. Thus, there is no evidence for a metabolic separation of the catabolism of these two carbon sources.
Goupry
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S
Laboratoire d'Analyse Isotopique et Electrochimique de Métabolismes, CNRS ESA 6006, Faculté des Sciences et des Techniques, 2 rue de la Houssinière, 44322, Nantes, France.
Croguennec
T
T
Gentil
E
E
Robins
R J
RJ
D000093:Acetoin / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism*; D003931:Diacetyl / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism*; D013294:Lactococcus lactis / Q000254:growth & development / Q000378:metabolism*; D013058:Mass Spectrometry
D002250:Carbon Radioisotopes; D019343:Citric Acid; D019344:Lactic Acid; D000093:Acetoin; D005947:Glucose; D003931:Diacetyl