Reference : Characterization of the response of GFP microbial biosensors sensitive to substrate limi...
Scientific journals : Article
Life sciences : Biotechnology
http://hdl.handle.net/2268/87991
Characterization of the response of GFP microbial biosensors sensitive to substrate limitation in scale-down bioreactors
English
Delvigne, Frank* mailto [Université de Liège - ULg > Chimie et bio-industries > Bio-industries >]
Brognaux, Alison* mailto [Université de Liège - ULg > > > Form. doct. sc. agro. & ingé. biol.]
Gorret, Nathalie [> >]
Neubauer, Peter [> >]
Delafosse, Angélique mailto [Université de Liège - ULg > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires >]
Collignon, Marie-Laure mailto [Université de Liège - ULg > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires >]
Toye, Dominique mailto [Université de Liège - ULg > Département de chimie appliquée > Génie de la réaction et des réacteurs chimiques >]
Crine, Michel mailto [Université de Liège - ULg > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires >]
Boxus, Mathieu mailto [Université de Liège - ULg > Chimie et bio-industries > Centre de Bio. Fond. - Section de Biologie cell. et moléc. >]
Thonart, Philippe mailto [Université de Liège - ULg > Département des sciences de la vie > Biochimie et microbiologie industrielles >]
* These authors have contributed equally to this work.
2011
Biochemical Engineering Journal
Elsevier Science
55
2
131-139
Yes (verified by ORBi)
International
1369-703X
Lausanne
Switzerland
[en] The dynamics of microbial stress response in intensive cultivation conditions remains not completely understood. In this work, two green fluorescent protein (GFP) transcriptional reporters have been used as biosensors of the heterogeneities generated in a two-compartment scale-down reactor. The stress promoters have been chosen for their responsiveness to carbon limitation corresponding to the global substrate profiles encountered in intensive fed-batch cultures. From our results, it can be concluded that the exposure of microbial cells to substrates heterogeneities tends to decrease the GFP expression level in fed-batch mode. Fluorescence intensities have been monitored at the single cell level by using flow cytometry. During the course of the fed-batch culture, a drop at the level of the intracellular GFP content has been observed for the two scale-down operating conditions and for the two promoters sensitive to substrate limitation (rpoS and csiE). The fluorescence drop can be attributed to the repression of these promoters but also to the release of GFP to the extracellular medium according to the increase of the fluorescence level of the supernatant. This leakage has been observed for all the operating conditions, i.e. the scale-down reactors and the culture operating in the normal mode, i.e. in a well-mixed bioreactor. Interestingly, GFP leakage is more pronounced in the case of the cultures operated in the normal mode. Indeed, staining by propidium iodide tends to be more elevated for the microbial cells cultured under the normal mode by comparison with those cultured in scale-down conditions, indicating a higher permeability of the membrane. These results suggest that GFP microbial biosensors could be used to detect simultaneously mixing imperfections and their impact on the viability of microorganisms.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS, FRIA ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS, FRFC
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/87991

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