Diacetyl and α-Acetolactate Overproduction by Lactococcus lactis subsp. lactis Biovar Diacetylactis Mutants That Are Deficient in α-Acetolactate Decarboxylase and Have a Low Lactate Dehydrogenase Activity

• DOI: 10.1128/aem.66.12.5518-5520.2000
• Publication Date: 2002-07-27T09:55:30Z
• Authors: Christophe Monnet; Frédéric Aymes; Georges Corrieu
• Keywords: Acetoin; Biovar; Diacetyl; Acetolactate synthase

ABSTRACT Lactococcus lactis subsp. biovar diacetylactis strains are utilized in several industrial processes for producing the flavoring compound diacetyl or its precursor α-acetolactate. Using random mutagenesis with nitrosoguanidine, we selected mutants that were deficient α-acetolactate decarboxylase and had low lactate dehydrogenase activity. The produced large amounts of anaerobic milk cultures but not aerobic cultures, except when medium was supplemented catalase, yeast extract, hemoglobin.