Influence of citrate on the diacetyl and acetoin production by fully grown cells ofStreptococcus lactis subsp.diacetylactis

Petit, Christine; Vilchez, F.; Marczak, R.

doi:10.1007/bf01570108

Cited by 16 publications

(6 citation statements)

References 14 publications

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“…A number of lines of evidence have been interpreted as indicating that lactic acid is principally derived from glucose but that diacetyl and acetoin are primary produced from citrate. Notably, (1) fermentations conducted in the absence of citrate accumulate negligible amounts of these aromatic compounds ; (2) diacetyl and acetoin have been reported to accumulate late in the fermentation period, coincident with the period after citrate catabolism has started [4]; (3) aerobic fermentations favor diacetyl and acetoin accumulation, in accord with the oxidative metabolism of citrate [5].…”

Section: Introductionmentioning

confidence: 99%

Metabolic flux in glucose/citrate co-fermentation by lactic acid bacteria as measured by isotopic ratio analysis

Goupry¹,

Croguennec²,

Gentil³

et al. 2000

FEMS Microbiology Letters

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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.

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Section: Introductionmentioning

confidence: 99%

Metabolic flux in glucose/citrate co-fermentation by lactic acid bacteria as measured by isotopic ratio analysis

Goupry¹,

Croguennec²,

Gentil³

et al. 2000

FEMS Microbiology Letters

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“…The extent of formation of these aroma compounds depends on the L. lactis strain (7), the citrate concentration in the medium (8,18,19), the presence of hemin and/or metal ions such as Cu2+ (13), temperature and pH (20), and cell immobilization (21,22).…”

mentioning

confidence: 99%

Effect of Initial Oxygen Concentration on Diacetyl and Acetoin Production by Lactococcus lactis subsp. lactis biovar diacetylactis

Bassit

Boquien

Picque

et al. 1993

Appl Environ Microbiol

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The production of aroma compounds (acetoin and diacetyl) in fresh unripened cheese by Lactococcus lactis subsp. lactis biovar diacetylactis CNRZ 483 was studied at 30°C at different initial oxygen concentrations (0, 21, 50, and 100% of the medium saturation by oxygen). Regardless of the initial 02 concentration, maximal production of these compounds was reached only after all the citrate was consumed. Diacetyl and acetoin production was 0.01 and 2.4 mM, respectively, at 0% oxygen. Maximum acetoin concentration reached 5.4 mM at 100% oxygen. Diacetyl production was increased by factors of 2, 6, and 18 at initial oxygen concentrations of 21, 50, and 100,o respectively. The diacetylacetoin concentration ratio increased linearly with initial oxygen concentration: it was eight times higher at 100% (3.3%) than at O%o oxygen (0.4%). The effect of oxygen on diacetyl and acetoin production was also shown with other lactococci. At 01% oxygen, specific activity of a-acetolactate synthetase (0.15 U/mg) and NADH oxidase (0.04 U/mg) was 3.6 and 5.4 times lower, respectively, than at 100o oxygen. The increasing cv-acetolactate synthetase activity in the presence of oxygen would explain the higher production of diacetyl and acetoin. The NADH oxidase activity would replace the role of the lactate dehydrogenase, diacetyl reductase, and acetoin reductase in the reoxidation of NADH, allowing accumulation of these two aroma compounds.

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“…Acetoin exerts an inhibitory effect on the acetoin reductase activity if its concentration exceeds 1 mM [3]. When the pH, the growth temperature and the storage temperature diminish to 4.5, 18˚C and between 2˚C and 5˚C, respectively, the reductase activity of the DAR is strongly inhibited in cpLN and LD cells; the diacetyl pool is favored [24] [56]- [59]. The gene encoding for the DAR/BDH is carried on the chromosome in Lc lactis whereas in Ln pseudomesenteroides, this enzyme seems to be plasmid-encoded [60] (…”

Section: Inhibitory Factorsmentioning

confidence: 99%

The Citrate Metabolism in Homo- and Heterofermentative LAB: A Selective Means of Becoming Dominant over Other Microorganisms in Complex Ecosystems

Pascal¹,

Demarigny²

2014

FNS

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The citrate metabolism has been extensively studied in lactic acid bacteria (LAB) for its aroma compound production. Among the 4-carbon (C4) by-products obtained from citrate fermentation, diacetyl is one of the better known products for its contribution to the buttery aroma of dairy products. A lot of documents deal with ways to improve diacetyl concentration in food matrices. Apart from these organoleptic advantages, in a microbial ecosystem, the citrate metabolism gives selective advantages to citrate positive microorganisms. Citrate metabolism allows the LAB to use another carbon source for their growth, withstand acidic conditions and generate a "proton motive force" (PMF). Moreover, the citrate/glucid co-metabolism leads to the fast release of organic compounds known for having bacteriostatic effects. Under specific conditions, the C4 pathway liberates diacetyl which is bacteriostatic. In this review we first describe the citrate metabolism and the enzymes involved in the two homo-and heterofermentative LAB Lc diacetylactis and Leuconostoc spp. Moreover, the way to shift the metabolic pathway toward the production of aromatic compounds is discussed for both of these fermentative types of bacteria. Finally, the selective advantages of citrate metabolism for LAB in complex microbial ecosystems are delineated.

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Influence of citrate on the diacetyl and acetoin production by fully grown cells ofStreptococcus lactis subsp.diacetylactis

Cited by 16 publications

References 14 publications

Metabolic flux in glucose/citrate co-fermentation by lactic acid bacteria as measured by isotopic ratio analysis

Metabolic flux in glucose/citrate co-fermentation by lactic acid bacteria as measured by isotopic ratio analysis

Effect of Initial Oxygen Concentration on Diacetyl and Acetoin Production by Lactococcus lactis subsp. lactis biovar diacetylactis

The Citrate Metabolism in Homo- and Heterofermentative LAB: A Selective Means of Becoming Dominant over Other Microorganisms in Complex Ecosystems

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