Effets de l'hydrodynamique et du transfert d'oxygène sur la physiologie de Streptomyces pristinaespiralis lors de cultures en flacons agités

Abstract : During this study, the physiology of Streptomyces pristinaespiralis and more specifically the production of pristinamycins (induction and concentration) were related to its hydrodynamic environment. Cultures of S. pristinaespiralis were performed under various conditions of agitation and aeration in non baffled Erlenmeyer flasks. According to the operating conditions, the volume power dissipation was from 0.55 to 14 kW.m-3 while kLa was from 30 to 490 h-1. Based on the observation of the complexity of both hydrodynamics encountered in bioreactors and of the cellular response, a multiscale and multidisciplinary approach between process engineering and quantitative physiology was developed. The apparent physiological response was quantified in terms of growth, substrates consumption, morphology and production. The hydrodynamics of the shake flasks was described using Computational Fluid Dynamics. Using an original break up model, the pellet diameters were correlated to the Kolmogorov dissipation scale. Moreover, it was shown that pellet growth was slowed down by the dissipation scale increase. Then, by decoupling the agitation and the aeration, it was shown that the pellets size, controlled by turbulence, impacted directly the consumption of oxygen and the concentration of pristinamycins. Furthermore, onset of pristinamycin production resulted in a limitation in nitrogen substrates as well as a sufficient oxygen supply which are determined by the oxygen transfer and the volume power dissipation
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Nasir Mehmood. Effets de l'hydrodynamique et du transfert d'oxygène sur la physiologie de Streptomyces pristinaespiralis lors de cultures en flacons agités. Autre. Institut National Polytechnique de Lorraine, 2011. Français. ⟨NNT : 2011INPL016N⟩. ⟨tel-01748879⟩

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