Polymérisation et suroxydation du polypyrrole par FeCl

Une amélioration de la conductivité du polypyrrole, synthétisé dans l'eau par oxydation du pyrrole par FeCl3, est obtenue par ajout de FeCl2 dans le milieu. Cette amélioration résulte d'un ralentissement de l'attaque nucléophile par l'eau de la chaîne polymérique en croissance. Cet ajout de FeCl2 se traduit aussi par un ralentissement de la polymérisation

Effects of bioreactor hydrodynamics on the physiology of Streptomyces

International audienceStreptomyces are filamentous bacteria which are widely used industrially for the production of therapeutic biomolecules, especially antibiotics. Bioreactor operating conditions may impact the physiological response of Streptomyces especially agitation and aeration as they influence hydromechanical stress, oxygen and nutrient transfer. The understanding of the coupling between physiological response and bioreactor hydrodynamics lies on a simultaneous description of the flow and transfers encountered by the bacteria and of the microbial response in terms of growth, consumption, morphology, production or intracellular signals. This article reviews the experimental and numerical works dedicated to the study of the coupling between bioreactor hydrodynamics and antibiotics producing Streptomyces. In a first part, the description of hydrodynamics used in these works is presented and then the main relations used. In a second part, the assumptions made in these works are discussed and put into emphasize. Lastly, the various Streptomyces physiological responses observed are detailed and compared