title: Diacetyl and alpha-acetolactate overproduction by Lactococcus lactis subsp. lactis biovar diacetylactis mutants that are deficient in alpha-acetolactate decarboxylase and have a low lactate dehydrogenase activity.
abstract: Lactococcus lactis subsp. lactis biovar diacetylactis strains are utilized in several industrial processes for producing the flavoring compound diacetyl or its precursor alpha-acetolactate. Using random mutagenesis with nitrosoguanidine, we selected mutants that were deficient in alpha-acetolactate decarboxylase and had low lactate dehydrogenase activity. The mutants produced large amounts of alpha-acetolactate in anaerobic milk cultures but not in aerobic cultures, except when the medium was supplemented with catalase, yeast extract, or hemoglobin.
authors.affiliation: Laboratoire de Génie et Microbiologie des Procédés Alimentaires, Institut National de la Recherche Agronomique, 78850 Thiverval-Grignon, France. monnet@grignon.inra.fr
authors.forename: C
authors.initials: C
authors.lastname: Monnet
authors.forename: F
authors.initials: F
authors.lastname: Aymes
authors.forename: G
authors.initials: G
authors.lastname: Corrieu
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D003931:Diacetyl / Q000378:metabolism*; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007773:Lactates / Q000378:metabolism*; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*
chemical_list: D003470:Culture Media; D007773:Lactates; C006359:alpha-acetolactate; D007770:L-Lactate Dehydrogenase; D002262:Carboxy-Lyases; C023746:acetolactate decarboxylase; D003931:Diacetyl