Influence of Oxygen and pH on Methanethiol Production from l-Methionine by Brevibacterium linens CNRZ 918.
The effects of dissolved oxygen concentration and pH on the growth of Brevibacterium linens CNRZ 918 and its production of methanethiol from l-methionine were investigated. Optimal specific methanethiol production was obtained at 25% saturation of dissolved oxygen and at a pH between 8 and 9, whereas optimal cell growth occurred at 50% oxygen saturation and when the pH was maintained constantly at 7. Methanethiol production by nonproliferating bacteria required the presence of l-methionine (7 mM) in the culture medium. This was probably due to the induction of enzyme systems involved in the process. The intracellular concentration of l-methionine seemed to play a key role in this process. B. linens CNRZ 918 tolerated alkaline pHs with a maximal growth pH of approximately 9. Its orange pigmentation seemed to depend on the presence of l-methionine in the culture medium and on the concentration of dissolved oxygen.
Ferchichi
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Laboratoire de Microbiologie Laitière, Institut National de la Recherche Agronomique, Centre National de Recherches Zootechniques, 78350 Jouy-en-Josas, France.
Hemme
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D
Bouillanne
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