Genetic manipulation of the pathway for diacetyl metabolism in Lactococcus lactis.
Diacetyl is an important food flavor compound produced by certain strains of citrate-metabolizing lactic acid bacteria. Citrate is converted to pyruvate, from which diacetyl is produced via intermediate alpha-acetolactate. This paper reports the cloning and analysis of the gene (aldB) encoding alpha-acetolactate decarboxylase from Lactococcus lactis MG1363. Deletion of the MG1363 chromosomal aldB gene was achieved by double crossover homologous recombination. The mutant strain was found to produce diacetyl; alpha-acetolactate decarboxylase activity was eliminated. Overexpression of the cloned ilvBN genes (encoding an alpha-acetolactate synthase) in the aldB deletion strain produced even higher levels of alpha-acetolactate, acetoin, and diacetyl.
Swindell
S R
SR
Institute of Food Research, Colney, United Kingdom.
Benson
K H
KH
Griffin
H G
HG
Renault
P
P
Ehrlich
S D
SD
Gasson
M J
MJ
D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D003931:Diacetyl / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D005798:Genes, Bacterial; D007773:Lactates / Q000096:biosynthesis; D013294:Lactococcus lactis / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data
D017931:DNA Primers; D004269:DNA, Bacterial; D007773:Lactates; C006359:alpha-acetolactate; D000095:Acetolactate Synthase; D002262:Carboxy-Lyases; C023746:acetolactate decarboxylase; D003931:Diacetyl