Entrapment of l-tryptophan producing Escherichia coli in different matrices: activity of immobilized cells |
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Authors: | Sylvie Langrene Sames Sicsic François Le Goffic |
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Institution: | Centre d''Etudes et de Recherches de Chimie Organique Appliquée, CNRS, Laboratoire associé à l''ENSCP, 2–8, rue Henry Dunant, 94320 Thiais, France |
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Abstract: | Cells of Escherichia coli induced for l-tryptophan synthase l-serine hydro-lyase (adding indole-glycerol-phosphate), EC 4.2.1.20] have been assayed in DMF and DMSO aqueous solvents as reaction medium. Up to 20% DMF/water, cells retained 90% of their tryptophan synthase activity. Concentrations of 20 mM indole, which did not inhibit this reactivity, could be reached with 5% DMF/water. Four matrices were compared for cell immobilization: polyacrylamide, foam particles of bovine seum albumin, alginate and κ-carrageenan. The best activity was retained with the latter matrix, and the preparations thus obtained allowed high productivity of l-tryptophan. Various systems of production of l-tryptophan with κ-carrageenan and DMF/water were studied. |
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Keywords: | Escherichia coli immobilization organic solvents |
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