Dual influence of the carbon source and L-methionine on the synthesis of sulphur compounds in the cheese-ripening yeast Geotrichum candidum.
The effect of the carbon source and l-methionine on the ability of Geotrichum candidum to produce volatile sulphur compounds (VSC) was studied. This yeast was cultivated in a synthetic medium supplemented with various carbon sources and l-methionine at different concentrations. Both glycerol and glucose significantly increased VSC production by G. candidum. Unlike the effect on the l-methionine- and 4-methylthio-2-oxobutyric acid-demethiolating activities, the supply of a carbon source had a dramatic effect on the activity of aminotransferase, a key enzyme in l-methionine catabolism. An increase in the initial concentration of l-methionine resulted in a rise in the production of sulphur compounds (VSC, 4-methylthio-2-oxobutyric acid) but had limited effect on l-methionine-catabolising enzyme activities. Evidence for the existence of a dual effect of the carbon source and l-methionine on VSC biosynthesis was obtained in this study.
Laboratoire de Génie et Microbiologie des Procédés Alimentaires, Institut National de la Recherche Agronomique, 78850 Thiverval-Grignon, France.
K
K
Arfi
R
R
Tâche
H E
HE
Spinnler
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P
Bonnarme
D002087:Butyrates / Q000378:metabolism; D002611:Cheese / Q000382:microbiology*; D003470:Culture Media; D005848:Geotrichum / Q000254:growth & development / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D008715:Methionine / Q000378:metabolism*; D013438:Sulfhydryl Compounds; D013457:Sulfur Compounds / Q000378:metabolism*
D002087:Butyrates; D003470:Culture Media; D013438:Sulfhydryl Compounds; D013457:Sulfur Compounds; D019344:Lactic Acid; C045636:2-keto-4-mercaptobutyric acid; D008715:Methionine; D005947:Glucose; D005990:Glycerol