Characterization of brackish anaerobic bacteria involved in hydrocarbon degradation: A combination of molecular and culture-based approaches

cited By 11International audienceAnaerobic bacterial communities were selected by successive enrichments, under light conditions, on selected hydrocarbon molecules (aliphatic and aromatic). The original inocula came from an oil-contaminated microbial mat developing in a refinery waste water treatment plant in Berre Lagoon (Mediterranean Sea, France). Bacterial communities able to degrade octadecane, naphthalene and fluoranthene were obtained. By using molecular methods (T-RFLP, ARDRA and sequencing), the composition of these bacterial communities were determined in order to identify the organisins involved in hydrocarbon degradation. Different functional groups, including denitrifiers, sulfate-reducers, anoxygenic phototrophs and fermentative bacteria could be identified. Molecular techniques permitted identification of the different functional groups and were therefore useful in the isolation of the key organisms involved in hydrocarbon degradation. Not all of these populations were able to utilize hydrocarbons as carbon source and/or electron donor. Indeed, among the different pure strains recovered from such enrichment cultures, some actively degraded hydrocarbon molecules (denitrifiers) whereas others have an indirect role (synergism, surfactant production). For example, several anoxygenic phototrophs have been isolated in pure culture and none use hydrocarbons for growth. Nevertheless, in addition to sulphide reoxidation originating from sulfate reduction, these microorganisms may play an important role in surfactant productio

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 %)

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

Characterization of extracellular polymers synthesized by tropical intertidal biofilm bacteria

Aims: This study was performed to determine the potential of tropical intertidal biofilm bacteria as a source of novel exopolymers (EPS). Methods and Results: A screening procedure was implemented to detect EPS-producing biofilm bacteria. Isolates MC3B-10 and MC6B-22, identified respectively as a Microbacterium species and Bacillus species by 16S rDNA and cellular fatty acids analyses, produced different EPS, as evidenced by colorimetric and gas chromatographic analyses. The polymer produced by isolate MC3B-10 displays significant surfactant activity, and may chelate calcium as evidenced by spectroscopic analysis. Conclusions: Polymer MC3B-10 appears to be a glycoprotein, while EPS MC6B-22 seems to be a true polysaccharide dominated by neutral sugars but with significant concentrations of uronic acids and hexosamines. EPS MC3B-10 possesses a higher surfactant activity than that of commercial surfactants, and given its anionic nature, may chelate cations thus proving useful in bioremediation. The chemical composition of polymer MC6B-22 suggests its potential biomedical application in tissue regeneration. Significance and Impact of the Study: This is the first report of a Microbacterium species producing EPS with surfactant properties, which expands our knowledge of the micro-organisms capable of producing these biomolecules. Furthermore, this work shows that tropical intertidal environments are a nonpreviously recognized habitat for bioprospecting EPS-producing bacteria, and that these molecules might be involved in ecological roles protecting the cells against dessication