Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

LA/P/0140/202019 UID/AGR/04129/2020 LA/P/0037/2020This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7–6.1 × 10−11 mol m−1 s−1 Pa−1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6–47.0%), low tensile strength at break (Ꞇ) (4.55–11.7 MPa) and low Young’s modulus (εm) (10–93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6–23.6 MPa), lower ε (2.80–5.58%), and higher εm (597–1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.publishersversionpublishe

Le Forest Rights Act, vers une légalisation des pratiques locales dans les forêts indiennes ?

International audienceno abstrac

Marques, indications géographiques et certifications : comment valoriser la biodiversité dans les Ghâts occidentaux (Inde) ?

International audienceThe district of Kodagu (Coorg) in India produces between 1 and 2 % of the world’s coffee, in multi-strata agro-forestry systems embedded between paddy fields and evergreen rainforest fragments. This complex landscape is rapidly changing. The forests have been converted into coffee plantations, the native species that form the rich canopy cover of the plantations are being replaced with exotic and fast growing species and the conflicts between humans and wildlife are increasing. In this context, we explore the potential for linking livelihood development and biodiversity conservation offered by three value-addition approaches centered on the localized productions of the district. The first one relies on trademarks comprising the name “Coorg ” for marketing coffee. The second is based on the existing indian Geographical Indications legal framework, which has yet to be used for coffee from Coorg. The third one rests on the development of environmental certifications for the coffees from India. We assess the social and ecological efficiency of these three strategies and propose an analysis of the questions raised by the different degrees of implication of the stakeholders and beneficiaries of such approaches.Le district du Kodagu (Coorg) en Inde produit entre 1 et 2 % du café mondial, dans des systèmes agroforestiers complexes imbriqués entre des rizières et des fragments de forêts sempervirentes humides. Cette mosaïque paysagère évolue rapidement. La forêt a reculé au profit des plantations, le couvert arboré riche en espèces natives est progressivement remplacé par une espèce exotique et les conflits avec la faune se font plus fréquents. Dans ce contexte, trois stratégies de valorisation commerciale sont explorées, avec une attention particulière à leur potentiel pour associer développement économique et conservation de la biodiversité. La première approche repose sur l’utilisation de marques commerciales comprenant le nom « Coorg » pour du café. La seconde approche est basée sur les perspectives offertes par les indications géographiques, qui font l’objet d’une dynamique remarquable en Inde mais qui n’ont pas encore été mobilisées pour le café de Coorg. La troisième s’appuie sur l’émergence des certifications environnementales pour le café en Inde. Nous proposons une analyse de l’efficacité sociale et environnementale de ces trois stratégies ainsi qu’une lecture des questions soulevées par l’implication différentielle des acteurs porteurs et/ou usagers potentiels de ces démarches

Discovery of a mcl-PHA with unexpected biotechnical properties: the marine environment of French Polynesia as a source for PHA-producing bacteria

International audienceA library of microorganisms originating from various marine environments in French Polynesia was screened for polyhydroxyalkanoate producing bacteria. No significant connection was found between the geo‑ecological source of bacteria and their ability to produce polyhydroxyalkanoate. A bacterial strain designated as Enterobacter FAK 1384 was isolated from a shark jaw. When grown on coprah oil, this bacterium produces a PHA constituting of 62 mol % 3‑hydroxydecanoate and lower amount of 12 mol % 3‑hydroxydodecenoate and of 7.6 mol % 3‑hydroxydodecanoate. These interesting properties make this mcl‑PHA a good candidate for further exploitations in many industrial sectors, as in film and coating manufacturing, as well as for biomedical applications

MOESM1 of Discovery of a mcl-PHA with unexpected biotechnical properties: the marine environment of French Polynesia as a source for PHA-producing bacteria

Additional file 1: Fig. S1. The multiple correspondence analysis performs a multivariate analysis, with categorical and quantitative variables. Two individuals are close to each other if they shared the same traits (variables). The green triangles show the presence or absence of PHA between the different associations. Isolates are shown in blue. MarSed: Marine sediment, MicroMat: Microbial mats, MarFilm: Marine film and MarAni: Marine animals. Fig. S2: The maximum-likelihood reconstruction of the 16S nuclear ribosomal DNA genotypes of Enterobacter shows the phylogenetic position of FAK1384 within the genera Enterobacter. Accession numbers are put in brackets. Node numbers indicate percentage bootstrap support from 500 replicates. Nodes without bootstrap values were supported by less than 75 % of the replicates. Table S1: 25 out of the 70 tested isolates show a significant PHA production ability (> 15 %)

Aerosols over the ESCOMPTE domain: overwhelming importance of the secondary aerosol formation

2-4 février 200

Structure, rheology, and copper-complexation of a hyaluronan-like exopolysaccharide from Vibrio

MO245 exopolysaccharide (EPS) was produced in laboratory conditions from Vibrio genus microorganism isolated from bacterial mats found in Moorea Island. Its structure consists of a linear tetrasaccharide repeating unit â 4)-β-D-GlcpA-(1â 4)-α-D-GalpNAc-(1â 3)-β-D-GlcpNAc-(1â 4)-β-D-GlcpA-(1â containing covalently-linked 5% of glucose, galactose, and rhamnose, determined by methylation analyses and NMR spectroscopy. The molecular weight, radius of gyration (Rg) and intrinsic viscosity, [η], determined by gel permeation chromatography with light scattering and viscosity detection, were 513â ±â 4â kDa (PDI, 1.42â ±â 0.01), 6.7â ±â 0.3â dl/g and 56â ±â 0.3â nm respectively. The chelation of the EPS with copper divalent ions leads to the instantaneous formation of gels. The structural similitude proposed, based in an equal ratio of GlcA to N-acetylated sugars and in the same type of glyosidic linkages present in the repeating unit (alternated 1â 3 and 1â 4 linkages), is translated into analogous physicochemical properties: MO245 EPS is a flexible polyelectrolyte, with scaling exponents similar to that described for HA. This similitude opens opportunities in future drug delivery, tissue engineering, and cosmetic applications.RIAIDT, CACTUS at the University of Santiago de Compostela and in the "Manuel Rico" NMR laboratory (LMR) of the Spanish National Research Council (CSIC) were the 750 MHz and 800 MHz NMR spectra were carried out respectively. FCT/MEC for the financial support to CICECO (FCT UID /CTM /50011/2013; POCI-01-0145-FEDER-007679) and QOPNA research Unit (FCT UID/QUI/00062/2013), through national founds and co-financed by the FEDER, within the PT2020 Partnership Agreement. RNC (IF/00373/2014), CN (SFRH/BPD/100627/2014), and ASF (SFRH/BD/102471/2014) thank the FCT foundation for funding