Characterization of the effects of n-butanol on the cell envelope of E. coli.
Biofuel alcohols have severe consequences on the microbial hosts used in their biosynthesis, which limits the productivity of the bioconversion. The cell envelope is one of the most strongly affected structures, in particular, as the external concentration of biofuels rises during biosynthesis. Damage to the cell envelope can have severe consequences, such as impairment of transport into and out of the cell; however, the nature of butanol-induced envelope damage has not been well characterized. In the present study, the effects of n-butanol on the cell envelope of Escherichia coli were investigated. Using enzyme and fluorescence-based assays, we observed that 1 % v/v n-butanol resulted in the release of lipopolysaccharides from the outer membrane of E. coli and caused 'leakiness' in both outer and inner membranes. Higher concentrations of n-butanol, within the range of 2-10 % (v/v), resulted in inner membrane protrusion through the peptidoglycan observed by characteristic blebs. The findings suggest that strategies for rational engineering of butanol-tolerant bacterial strains should take into account all components of the cell envelope.
School of Biological Sciences, University of Edinburgh, Edinburgh, UK. eukaf@biosustain.dtu.dk.|Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh, UK. eukaf@biosustain.dtu.dk.|Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Lyngby, DK, Denmark. eukaf@biosustain.dtu.dk.
Eugene
http://orcid.org/0000-0002-5146-4628
E
Fletcher
School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh, UK.|Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Lyngby, DK, Denmark.
Teuta
T
Pilizota
School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh, UK.|Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Lyngby, DK, Denmark.
Philip R
PR
Davies
School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh, UK.|Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Lyngby, DK, Denmark.
Alexander
A
McVey
School of Biological Sciences, University of Edinburgh, Edinburgh, UK.|Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh, UK.|Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet Bygning 220, 2800, Lyngby, DK, Denmark.
Chris E
CE
French
D020001:1-Butanol / Q000378:metabolism* / Q000633:toxicity*; D002462:Cell Membrane / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects*
D020001:1-Butanol
Bacteria; Biofuel; Cell membrane; n-butanol