Cultivation of an immobilized (hyper)thermophilic marine microbial community in a bioreactor.

Cultivation in a bioreactor of immobilized deep-sea hydrothermal microbial community was tested in order to assess the stability and reactivity of this new system. A community composed of eight hydrothermal strains was entrapped in a polymer matrix that was used to inoculate a continuous culture in a gas-lift bioreactor. The continuous culture was performed for 41 days at successively 60°C, 55°C, 60°C, 85°C and 60°C, at pH 6.

Entrapment of anaerobic thermophilic and hyperthermophilic marine micro-organisms in a gellan/xanthan matrix.

Aims: The aims of this study were (i) to develop a protocol for the entrapment of anaerobic (hyper)thermophilic marine micro-organisms; (ii) to test the use of the chosen polymers in a range of physical and chemical conditions and (iii) to validate the method with batch cultures.

Methods And Results: The best conditions for immobilization were obtained at 80°C with gellan and xanthan gums. After 5-week incubation, beads showed a good resistance to all tested conditions except those simultaneously including high temperature (100°C), low NaCl (<0∙5 mol l(-1) ) and extreme pH (4/8).

Phaeobacter leonis sp. nov., an alphaproteobacterium from Mediterranean Sea sediments.

A novel Gram-stain-negative, strictly aerobic, heterotrophic bacterium, designated 306(T), was isolated from near-surface (109 cm below the sea floor) sediments of the Gulf of Lions, in the Mediterranean Sea. Strain 306(T) grew at temperatures between 4 and 32 °C (optimum 17-22 °C), from pH 6.5 to 9.

DNA extractions from deep subseafloor sediments: novel cryogenic-mill-based procedure and comparison to existing protocols.

Extracting DNA from deep subsurface sediments is challenging given the complexity of sediments types, low biomasses, resting structures (spores, cysts) frequently encountered in deep sediments, and the potential presence of enzymatic inhibitors. Promising results for cell lysis efficiency were recently obtained by use of a cryogenic mill (Lipp et al., 2008).

Stability of microbial communities in goat milk during a lactation year: molecular approaches.

The microbial communities in milks from one herd were evaluated during 1-year of lactation, using molecular methods to evaluate their stability and the effect of breeding conditions on their composition. The diversity of microbial communities was measured using two approaches: molecular identification by 16S and 18S rDNA sequencing of isolates from counting media (two milks), and direct identification using 16S rDNA from clone libraries (six milks). The stability of these communities was evaluated by counting on selective media and by Single Strand Conformation Polymorphism (SSCP) analysis of variable region V3 of the 16S rRNA gene and variable region V4 of the 18S rRNA gene.