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Étude de la productivité et de la sélectivité de la biosynthèse de mycosubtiline, un antibiotique surfactant de Bacillus subtilis : apports du génie biochimique et de la transcriptomique

Abstract : The natural Bacillus subtilis strain ATCC 6633 has the ability to produce a wide range of antibacterial and antifungal antibiotics. Among these families of compounds, some are synthesized by the non-ribosomal pathway: fengycins, surfactins and mycosubtilins. The study of the biological activity of the mycosubtilins confirmed the broad spectrum of their antifungal action and showed the very strong antifungal activity of the anteisoC-17 isoform, particularly against Botrytis cinerea. A study of the environmental parameters contributed to the identification of culture conditions that made it possible to improve the productivity of mycosubtilin biosynthesis while limiting that of surfactin and to direct the cellular metabolism towards the biosynthesis of the most active isoform. The parameters tested were the following: culture media, pH, amino acid and iron additions, oxygen transfer. Several genes involved in central metabolic pathways, clearly related to the selectivity of this biosynthesis, ybgE, leuS, bfmBAA as well as the ilvBNCleuABCD operon, were then revealed through a transcriptomic study. The main genes coding for the regulators of these pathways, CodY, AbrB, ComK, CspB and CspC were also identified. The productivity of biosynthesis was finally improved by combining the use of a mycosubtilin overproducing derivative of B. Subtilis ATCC 6633 with the development of a bioreactor overflowing culture mode called O-EFBC.
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Contributor : Jean-Sébastien Guez <>
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Jean-Sebastien Guez. Étude de la productivité et de la sélectivité de la biosynthèse de mycosubtiline, un antibiotique surfactant de Bacillus subtilis : apports du génie biochimique et de la transcriptomique. Biotechnologies. Université des Sciences et Technologies de Lille, 2007. Français. ⟨tel-02939573⟩

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