Data/hora: 06/06/2024 04:32:20

Provedor de dados: | 5
País: | France

Título:

Immobilisation et culture continue en bioréacteur gas-lift de microorganismes marins thermophiles et hyperthermophiles anaérobies

Immobilization and continuous culture in gas-lift bioreactor of thermophilic and hyperthermophilic marine anaerobic microorganisms

Autores: | Landreau, Matthieu.
Data: | 2016-03-15
Ano: | 2016
Palavras-chave: | Immobilisation cellulaire; Gellane; Xanthane; Site Rainbow; Culture continue; Cell immobilization; Gellan; Xanthan; Rainbow site; (hyper)thermophile; Continuous culture.
Resumo: | Since the discovery of hydrothermal vents, multiple studies have been conducted in order to study microbial diversity. Molecular inventories realized have thus demonstrated a great diversity of species that contrasts with the low proportion (1%) of species isolated by culture approach. A new cell immobilization approach by inclusion in a polymer matrix (gellan and xanthan) has been developed for the study of these thermophilic anaerobic marine communities. The system, based on the formation of an emulsion between an inoculated polymer solution and oil, allows the entrapment of cells in gel beads with a diameter between 1 and 2 mm. The optimal immobilization conditions were obtained for emulsion performed at 80 °C with stirring (150 rpm) with a polymer solution composed of gellan (2.5%) and xanthan (0.25%) with 12 g/L of NaCl and 4 g/L of sodium citrate, bubbled with nitrogen and reduced with Na2S before inoculation. The beads showed a good mechanical stability after a 5-week incubation at pH between 5.4 and 8, temperatures up to 90 °C and NaCl and sulfur concentrations up to respectively 80 and 5 g/L. Batch cultures of immobilized Thermosipho sp. AT1272 and Thermococcus kodakarensis KOD1 yielded concentrations up to 107 cells/g of beads and 108 cells/mL of liquid fraction. A continuous culture performed in a gas-lift bioreactor for 41 days of an immobilized synthetic community composed of 8 (hyper)thermophilic strains demonstrated the capacity of cell immobilization to protect cells from oxique stress and to maintain them (3 of 8 strains) in the bioreactor until having suitable culture conditions for their growth. The reactivity of the immobilized community to environmental change (temperature) was also demonstrated. Finally, the continuous culture performed for 64 days of an immobilized diffuser sample from Rainbow site allowed the growth of several bacterial and archaeal species (Oceanithermus sp., Thermococcus sp.), part of which was detected only in the beads (Sulfurimonas sp., Nitratifractor sp., Vibrio sp.) by cloning-sequencing. All these results have validated the use of an immobilization protocol by inclusion in a polymer matrix for the study of hydrothermal communities, of their diversity and their dynamics.
Tipo: | Text
Idioma: | Francês

Identificador:

https://archimer.ifremer.fr/doc/00498/60933/64327.pdf

https://archimer.ifremer.fr/doc/00498/60933/

Editor: | Université de Bretagne occidentale
Formato: | application/pdf

Fonte:

info:eu-repo/semantics/openAccess

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