Diacetyl
Mostrando 25-36 de 117 artigos, teses e dissertações.
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25. Effect of Initial Oxygen Concentration on Diacetyl and Acetoin Production by Lactococcus lactis subsp. lactis biovar diacetylactis
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 O2 concentration, maximal production of these compounds was rea
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26. Diacetyl Biosynthesis in Streptococcus diacetilactis and Leuconostoc citrovorum
Pyruvate was shown to be the precursor of diacetyl and acetoin in Streptococcus diacetilactis, but dialyzed cell-free extracts of S. diacetilactis and Leuconostoc citrovorum that had been treated with anion-exchange resin to remove coenzyme A (CoA) formed only acetoin from pyruvate in the presence of thiamine pyrophosphate (TPP) and Mg++ or Mn++ ions. The ab
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27. The Caenorhabditis elegans seven-transmembrane protein ODR-10 functions as an odorant receptor in mammalian cells
The nematode Caenorhabditis elegans exhibits behavioral responses to many volatile odorants. Chemotaxis toward one such odorant, diacetyl (butanedione), requires the function of a seven-transmembrane receptor protein encoded by the odr-10 gene. To determine directly whether ODR-10 protein is an odorant receptor, it is necessary to express the protein in a he
The National Academy of Sciences of the USA.
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28. Plasmid-Encoded Diacetyl (Acetoin) Reductase in Leuconostoc pseudomesenteroides
A plasmid-borne diacetyl (acetoin) reductase (butA) from Leuconostoc pseudomesenteroides CHCC2114 was sequenced and cloned. Nucleotide sequence analysis revealed an open reading frame encoding a protein of 257 amino acids which had high identity at the amino acid level to diacetyl (acetoin) reductases reported previously. Downstream of the butA gene of L. ps
American Society for Microbiology.
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29. Transpeptidase Activity of Streptomyces D-Alanyl-D Carboxypeptidases
In the presence of Nα,Nε-diacetyl-L-Lys-D-Ala-D-Ala as donor, and either D-[14C]alanine, [14C]-glycine, or meso-[3H]diaminopimelic acid as acceptor, the DD carboxypeptidases from Streptomyces R61 and R39 catalyze a transpeptidation reaction with the release of terminal D-alanine from the donor and the formation of either Nα,Nε-diacetyl-L-Lys-D-Ala-D-[14C
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30. Control of Flavor Development in Wine during and after Malolactic Fermentation by Oenococcus oeni
During malolactic fermentation in wine by Oenococcus oeni, the degradation of citric acid was delayed compared to the degradation of malic acid. The maximum concentration of diacetyl, an intermediary compound in the citric acid metabolism with a buttery or nutty flavor, coincided with the exhaustion of malic acid in the wine. The maximum concentration of dia
American Society for Microbiology.
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31. Lactococcus lactis as a Cell Factory for High-Level Diacetyl Production
We report the engineering of Lactococcus lactis for the efficient conversion of sugar into diacetyl by combining NADH-oxidase overproduction and α-acetolactate decarboxylase inactivation. Eighty percent of the carbon flux was found to be rerouted via α-acetolactate to the production of diacetyl by preloading the cells with NADH-oxidase before their use as
American Society for Microbiology.
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32. Enzymatic Removal of Diacetyl from Beer 1: III. Enzyme Protection and Regeneration of Cofactor
Use of diacetyl reductase, a reduced nicotinamide adenine dinucleotide (NADH)-requiring enzyme, to eliminate diacetyl off-flavor in beer was studied. The crude enzyme was extracted from Aerobacter aerogenes and partially purified by ammonium sulfate precipitation or Sephadex chromatography. In the semipure state, the enzyme was inactivated by lyophilization;
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33. Esterases in Serum-Containing Growth Media Counteract Chloramphenicol Acetyltransferase Activity In Vitro
The spirochete Borrelia burgdorferi was unexpectedly found to be as susceptible to diacetyl chloramphenicol, the product of the enzyme chloramphenicol acetyltransferase, as it was to chloramphenicol itself. The susceptibilities of Escherichia coli and Bacillus subtilis, as well as that of B. burgdorferi, to diacetyl chloramphenicol were then assayed in diffe
American Society for Microbiology.
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34. A CYCLIC PATHWAY FOR THE BACTERIAL DISSIMILATION OF 2,3-BUTANEDIOL, ACETYLMETHYLCARBINOL AND DIACETYL II. : The Synthesis of Diacetylmethylcarbinol from Diacetyl, a New Diphosphothiamin Catalyzed Reaction1
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35. Properties of 2,3-Butanediol Dehydrogenases from Lactococcus lactis subsp. lactis in Relation to Citrate Fermentation
Two 2,3-butanediol dehydrogenases (enzymes 1 and 2; molecular weight of each, 170,000) have been partially purified from Lactococcus lactis subsp. lactis (Streptococcus diacetylactis) D10 and shown to have reductase activity with either diacetyl or acetoin as the substrate. However, the reductase activity with 10 mM diacetyl was far greater for both enzymes
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36. Biosynthesis of Diacetyl in Bacteria and Yeast
Both diacetyl and acetoin were produced by cell-free extracts and cultures of Pseudomonas fluorescens, Aerobacter aerogenes, Lactobacillus brevis, and Saccharomyces cerevisiae 299, whereas only acetoin was produced by cell-free extracts and cultures of Streptococcus lactis, Serratia marcescens, Escherichia coli, and S. cerevisiae strains 513 and 522. Cell-fr