Bacteria@Metal-Organic Frameworks (MOFs) for new bioremediation systems

Post-doctoral allowance,  12 months, AAP 2017-1

Team : ILV

Project leader : Clémence Sicard

Abstract :

The objective of this project is to design new bacterial immobilisation matrices based on Metal-Organic Frameworks (MOFs) to obtain novel multifunctional ‘living’ material for environmental remediation (water treatment). This unprecedented combination of MOFs and bacteria should allow us to prepare porous matrices with exceptional adsorption and synergetic degradation properties.

Micro-organisms have developed remarkable mechanisms to handle high concentrations of organic pollutants in their environment. In fact, microbial catalytic activity is currently the cornerstone for the degradation of organic matter in water treatment plants. In particular, some bacterial strains are known for their ability to degrade hazardous persistent organic pollutants (POP) such as polycyclic aromatic hydrocarbons (PAH), dioxins, pesticides among other substances listed as European priority pollutants. However, the use of microorganisms as biocatalytic entities often requires immobilisation within solid-supports, in order to provide protection, controlled environment, recyclability, recovery and to minimise leaching of exogenous strains. Even if numerous solid-hosts have been developed (e.g. calcium-alginate beads, clay-biopolymer nanocomposites or silica matrices…), new matrices able to combine chemical and mechanical stability with a finely controlled porosity for the diffusion of nutrients while minimising cell leaching, will widen the range of possible processing methods and applications.

Metal-Organic Frameworks (MOFs) are ideal candidates for the design of new bio-immobilisation matrices. Indeed, they are porous crystalline hybrid solids, built up from an almost infinite combination of inorganic subunits and organic polytopic linkers (carboxylates, azolates). Their versatile chemical composition (Lewis acid sites, redox centers, functional group on the organic ligand) and structural features make them promising materials for numerous applications. In particular due to their high surface area and tuneable physico-chemical properties, MOFs have demonstrated exceptional adsorption properties toward organic molecules (high capacity, selectively).

 In this project, we will elaborate new cellular immobilization matrices where the MOF acts, not only as a host support, but also provide specific adsorption properties towards pollutants. In fact, one of the most critical aspects in the biodegradation of apolar organic molecules in aqueous environment is related to their bioavailability, mostly dictated by their low solubility in water.

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LCMCP