Author:
Mozzetti Valeria,Grattepanche Franck,Moine Déborah,Berger Bernard,Rezzonico Enea,Meile Leo,Arigoni Fabrizio,Lacroix Christophe
Abstract
Abstract
Background
Oxidative stress can severely compromise viability of bifidobacteria. Exposure of Bifidobacterium cells to oxygen causes accumulation of reactive oxygen species, mainly hydrogen peroxide, leading to cell death. In this study, we tested the suitability of continuous culture under increasing selective pressure combined with immobilized cell technology for the selection of hydrogen peroxide adapted Bifidobacterium cells. Cells of B. longum NCC2705 were immobilized in gellan-xanthan gum gel beads and used to continuously ferment MRS medium containing increasing concentration of H2O2 from 0 to 130 ppm.
Results
At the beginning of the culture, high cell density of 1013 CFU per litre of reactor was tested. The continuous culture gradually adapted to increasing H2O2 concentrations. However, after increasing the H2O2 concentration to 130 ppm the OD of the culture decreased to 0. Full wash out was prevented by the immobilization of the cells in gel matrix. Hence after stopping the stress, it was possible to re-grow the cells that survived the highest lethal dose of H2O2 and to select two adapted colonies (HPR1 and HPR2) after plating of the culture effluent. In contrast to HPR1, HPR2 showed stable characteristics over at least 70 generations and exhibited also higher tolerance to O2 than non adapted wild type cells. Preliminary characterization of HPR2 was carried out by global genome expression profile analysis. Two genes coding for a protein with unknown function and possessing trans-membrane domains and an ABC-type transporter protein were overexpressed in HPR2 cells compared to wild type cells.
Conclusions
Our study showed that continuous culture with cell immobilization is a valid approach for selecting cells adapted to hydrogen peroxide. Elucidation of H2O2 adaptation mechanisms in HPR2 could be helpful to develop oxygen resistant bifidobacteria.
Publisher
Springer Science and Business Media LLC
Subject
Applied Microbiology and Biotechnology,Bioengineering,Biotechnology
Reference35 articles.
1. , : Joint FAO/WHO Working Group Report on Drafting Guidelines for the Evaluation of Probiotics in Food: April 30 and May 1, London, Ontario, Canada. 2002
2. Lacroix C, Yidirim S: Fermentation technologies for the production of probiotics with high viability and functionality. Curr Opin Biotechnol. 2007, 18: 176-183. 10.1016/j.copbio.2007.02.002.
3. Vasijevic T, Shah NP: Probiotics - From Metchnikoff to bioactives. Int Dairy J. 2008, 18: 714-728. 10.1016/j.idairyj.2008.03.004.
4. Simpson PJ, Ross RP, Fitzgerald GF, Stanton C: Bifidobacterium psychraerophilum sp. nov. and Aeriscardovia aeriphila gen. nov., sp. nov., isolated from a porcine caecum. Int J Syst Evol Microbiol. 2004, 54: 401-406. 10.1099/ijs.0.02667-0.
5. Biavati B, Mattarelli P: The family Bifidobacteriaceae. The Prokaryotes. Edited by: Falkow S, Rosenberg E, Schleifer KH, Stackebrandt E, Dworkin M. 2001, 322-382. New-York: Springer, 3
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