Skip to main content
NCBI home page
Applied and Environmental Microbiology logoLink to Applied and Environmental Microbiology
. 1996 Jul;62(7):2636–2640. doi: 10.1128/aem.62.7.2636-2640.1996

Imbalance of leucine flux in Lactococcus lactis and its use for the isolation of diacetyl-overproducing strains.

N Goupil 1, G Corthier 1, S D Ehrlich 1, P Renault 1
PMCID: PMC168043  PMID: 8779600

Abstract

Diacetyl is a by-product of pyruvate metabolism in Lactococcus lactis, where pyruvate is first converted to alpha-acetolactate, which is slowly decarboxylated to diacetyl in the presence of oxygen. L. lactis usually converts alpha-acetolactate to acetoin enzymatically, by alpha-acetolactate decarboxylase encoded by the aldB gene. We took advantage of the fact that this enzyme also has a central role in the regulation of branched-chain amino acids, to select spontaneous aldB mutants in an unbalanced concentration of leucine versus those of valine and isoleucine in the medium. Industrial dairy strains of L. lactis subsp. lactis biovar diacetylactis containing point mutations and deletions of aldB were isolated and characterized. Their growth in milk was not affected, but they rapidly accumulated a large amount of alpha-acetolactate instead of acetoin from citrate in milk. Under aerated condition, strains devoid of AldB produced about 10 times more diacetyl than did the parental strains.

Full Text

The Full Text of this article is available as a PDF (279.5 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bassit N., Boquien C. Y., Picque D., Corrieu G. Effect of Initial Oxygen Concentration on Diacetyl and Acetoin Production by Lactococcus lactis subsp. lactis biovar diacetylactis. Appl Environ Microbiol. 1993 Jun;59(6):1893–1897. doi: 10.1128/aem.59.6.1893-1897.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Cogan T. M., O'dowd M., Mellerick D. Effects of pH and Sugar on Acetoin Production from Citrate by Leuconostoc lactis. Appl Environ Microbiol. 1981 Jan;41(1):1–8. doi: 10.1128/aem.41.1.1-8.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Godon J. J., Chopin M. C., Ehrlich S. D. Branched-chain amino acid biosynthesis genes in Lactococcus lactis subsp. lactis. J Bacteriol. 1992 Oct;174(20):6580–6589. doi: 10.1128/jb.174.20.6580-6589.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Godon J. J., Delorme C., Bardowski J., Chopin M. C., Ehrlich S. D., Renault P. Gene inactivation in Lactococcus lactis: branched-chain amino acid biosynthesis. J Bacteriol. 1993 Jul;175(14):4383–4390. doi: 10.1128/jb.175.14.4383-4390.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Kaneko T., Takahashi M., Suzuki H. Acetoin Fermentation by Citrate-Positive Lactococcus lactis subsp. lactis 3022 Grown Aerobically in the Presence of Hemin or Cu. Appl Environ Microbiol. 1990 Sep;56(9):2644–2649. doi: 10.1128/aem.56.9.2644-2649.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kempler G. M., McKay L. L. Improved Medium for Detection of Citrate-Fermenting Streptococcus lactis subsp. diacetylactis. Appl Environ Microbiol. 1980 Apr;39(4):926–927. doi: 10.1128/aem.39.4.926-927.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  8. Marugg J. D., Goelling D., Stahl U., Ledeboer A. M., Toonen M. Y., Verhue W. M., Verrips C. T. Identification and characterization of the alpha-acetolactate synthase gene from Lactococcus lactis subsp. lactis biovar diacetylactis. Appl Environ Microbiol. 1994 Apr;60(4):1390–1394. doi: 10.1128/aem.60.4.1390-1394.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Phalip V., Monnet C., Schmitt P., Renault P., Godon J. J., Diviès C. Purification and properties of the alpha-acetolactate decarboxylase from Lactococcus lactis subsp. lactis NCDO 2118. FEBS Lett. 1994 Aug 29;351(1):95–99. doi: 10.1016/0014-5793(94)00820-5. [DOI] [PubMed] [Google Scholar]
  10. Platteeuw C., Hugenholtz J., Starrenburg M., van Alen-Boerrigter I., de Vos W. M. Metabolic engineering of Lactococcus lactis: influence of the overproduction of alpha-acetolactate synthase in strains deficient in lactate dehydrogenase as a function of culture conditions. Appl Environ Microbiol. 1995 Nov;61(11):3967–3971. doi: 10.1128/aem.61.11.3967-3971.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Ramos A., Jordan K. N., Cogan T. M., Santos H. C Nuclear Magnetic Resonance Studies of Citrate and Glucose Cometabolism by Lactococcus lactis. Appl Environ Microbiol. 1994 Jun;60(6):1739–1748. doi: 10.1128/aem.60.6.1739-1748.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Renault P., Godon J. J., Goupil N., Delorme C., Corthier G., Ehrlich S. D. Metabolic operons in Lactococci. Dev Biol Stand. 1995;85:431–441. [PubMed] [Google Scholar]
  13. Smid E. J., Konings W. N. Relationship between utilization of proline and proline-containing peptides and growth of Lactococcus lactis. J Bacteriol. 1990 Sep;172(9):5286–5292. doi: 10.1128/jb.172.9.5286-5292.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Snoep J. L., Teixeira de Mattos M. J., Starrenburg M. J., Hugenholtz J. Isolation, characterization, and physiological role of the pyruvate dehydrogenase complex and alpha-acetolactate synthase of Lactococcus lactis subsp. lactis bv. diacetylactis. J Bacteriol. 1992 Jul;174(14):4838–4841. doi: 10.1128/jb.174.14.4838-4841.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Speckman R. A., Collins E. B. Diacetyl biosynthesis in Streptococcus diacetilactis and Leuconostoc citrovorum. J Bacteriol. 1968 Jan;95(1):174–180. doi: 10.1128/jb.95.1.174-180.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Swindell S. R., Benson K. H., Griffin H. G., Renault P., Ehrlich S. D., Gasson M. J. Genetic manipulation of the pathway for diacetyl metabolism in Lactococcus lactis. Appl Environ Microbiol. 1996 Jul;62(7):2641–2643. doi: 10.1128/aem.62.7.2641-2643.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Terzaghi B. E., Sandine W. E. Improved medium for lactic streptococci and their bacteriophages. Appl Microbiol. 1975 Jun;29(6):807–813. doi: 10.1128/am.29.6.807-813.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Verhue W. M., Tjan F. S. Study of the Citrate Metabolism of Lactococcus lactis subsp. lactis Biovar Diacetylactis by Means of C Nuclear Magnetic Resonance. Appl Environ Microbiol. 1991 Nov;57(11):3371–3377. doi: 10.1128/aem.57.11.3371-3377.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES