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Identification et caractérisation des exopolymères de biofilms de bactéries marines

Abstract : In marine environment, artificial surfaces are promptly colonized by biofilms, which are communities of bacteria surrounded by matrix of extracellular polymeric substances (EPS). Formation of biofilm is a critical step of biofouling development, which corresponds to the accumulation of micro and macro-organisms on immersed surfaces and which can have important negative ramifications in particular in the marine sector. In this study, bacteria isolated from the Mediterranean Sea have been identified and characterized using different phenotypical tools. Their capacity to form a biofilm in vitro has been studied in different conditions, with a particular focus on their ability to produce abundant carbohydrate-rich EPS, the overall objective of the study being the isolation of original antifouling-active exopolysaccharides. Thirteen strains have been phylogenetically and phenotypically characterized. Seven genera and twelve species were identified among which two isolates were affiliated to a new species, named Persicivirga mediterranea. This genus has never been described in the Mediterranean Sea. Extraction of EPS of each strain, grown in biofilm conditions, allowed the determination of their general composition in carbohydrates, proteins, nucleic acids and lipids. One strain, Pseudoalteromonas ulvae TC14, was able to produce large quantities of exopolysaccharides, comprising in majority polymers of glucose whose chromatographic and spectroscopic analyzes revealed a diversity in size (Mw ~ 1-4000 kDa), charge (neutral or anionic) and associated function (acetate or lactate). These polysaccharides inhibited biofilm formed by other marine strains isolated from the Mediterranean Sea. They can also be synthesized by planktonic TC14, but in very different proportions.
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https://theses.hal.science/tel-01058255
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Submitted on : Tuesday, August 26, 2014 - 2:02:12 PM
Last modification on : Saturday, March 19, 2022 - 11:44:01 AM
Long-term archiving on: : Thursday, November 27, 2014 - 4:05:25 PM

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  • HAL Id : tel-01058255, version 1

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Florence Brian Brian-Jaisson. Identification et caractérisation des exopolymères de biofilms de bactéries marines. Microbiologie et Parasitologie. Université de Toulon, 2014. Français. ⟨NNT : 2014TOUL0003⟩. ⟨tel-01058255⟩

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