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Elaboration of cellularized hybrid macroporous materials by freeze-casting for soil bioremediation

Abstract : The goal of this work is the elaboration of new materials for soil depollution. The principle consists in the encapsulation of microorganisms with bioremediation capabilities in a hybrid porous matrix. Such matrix must be both compatible with the survival of the encapsulated organisms and suitable for the targeted application in terms of structure and in-soil stability. The choice of the components, as well as the processing techniques have a significant influence on these two aspects. The chosen microorganisms (the bacteria Pseudomonas aeruginosa and Shewanella oneidensis) were immobilized within a hybrid matrix, composed of biopolymer (pectin or alginate) as the organic moiety and silica as the inorganic moiety. The freeze-casting technique was used both as a way to encapsulate the microorganisms and to shape the biopolymer into a structure with an oriented porosity. Sol-gel chemistry was used to coat this structure with a silice layer, while ensuring survival of the encapsulated organisms thanks to mild synthetic conditions. This work allowed for the identification of key parameters both regarding the survival of microorganisms toward encapsulation and the final structure of the matrix. The influence of the freezing rate and of the composition of the matrix (type of biopolymer, presence of additives …) have in particular been investigated as a way to optimize bacterial survival rates upon encapsulation. The behavior of the materials was then assessed in a reference soil, from the point of view of the ageing of the matrix, but also regarding the efficiency of the device for soil depollution.
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Submitted on : Thursday, March 29, 2018 - 1:02:15 AM
Last modification on : Tuesday, September 22, 2020 - 3:40:02 AM
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  • HAL Id : tel-01746073, version 1

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Sarah Christoph. Elaboration of cellularized hybrid macroporous materials by freeze-casting for soil bioremediation. Chemical Physics [physics.chem-ph]. Université Pierre et Marie Curie - Paris VI, 2017. English. ⟨NNT : 2017PA066133⟩. ⟨tel-01746073⟩

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