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Cavity-enhanced Raman spectroscopy in the biosciences: In situ, multicomponent, and isotope selective gas measurements to study hydrogen production and consumption by Escherichia coli

Cavity-enhanced Raman spectroscopy in the biosciences: In situ, multicomponent, and isotope selective gas measurements to study hydrogen production and consumption by Escherichia coli
Cavity-enhanced Raman spectroscopy in the biosciences: In situ, multicomponent, and isotope selective gas measurements to study hydrogen production and consumption by Escherichia coli
Recently we introduced cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers as a sensitive analytical tool. Here we report improvements made on the technique and its first application in the biosciences for in situ, multicomponent, and isotope selective gas measure-ments to study hydrogen production and consumption by Escherichia coli. Under anaerobic conditions, cultures grown on rich media supplemented with D-glucose or glycerol produce H 2 and simultaneously consume some of it. By introducing D 2 in the headspace, hydrogen production and consumption could be separated due to the distinct spectroscopic signatures of isotopomers. Different phases with distinctly different kinetic regimes of H 2 and CO 2 production and D 2 consumption were identified. Some of the D 2 consumed is converted back to H 2 via H/D exchange with the solvent. HD was formed only as a minor component. This reflects either that H/D exchange at hydrogenase active sites is rapid compared to the rate of recombination, rapid recapture of HD occurs after the molecule is formed, or that the active sites where D 2 oxidation and proton reduction occur are physically separated. Whereas in glucose supplemented cultures, addition of D 2 led to an increase in H 2 produced, while the yield of CO 2 remained unchanged; with glycerol, addition of D 2 led not only to increased yields of H 2 , but also significantly increased CO 2 production, reflecting an impact on fermentation pathways. Addition of CO was found to completely inhibit H 2 production and significantly reduce D 2 oxidation, indicating at least some role for O 2 -tolerant Hyd-1 in D 2 consumption.
Raman, Spectroscopy, Biohydrogen
0003-2700
2147-2154
Smith, Thomas W.
890d7d44-ab77-46cd-9c24-803936f6ac99
Hippler, Michael
14b18bbd-6ebd-48c1-b1f0-c8161a18e40f
Smith, Thomas W.
890d7d44-ab77-46cd-9c24-803936f6ac99
Hippler, Michael
14b18bbd-6ebd-48c1-b1f0-c8161a18e40f

Smith, Thomas W. and Hippler, Michael (2017) Cavity-enhanced Raman spectroscopy in the biosciences: In situ, multicomponent, and isotope selective gas measurements to study hydrogen production and consumption by Escherichia coli. Analytical Chemistry, 89 (3), 2147-2154. (doi:10.1021/acs.analchem.6b04924).

Record type: Article

Abstract

Recently we introduced cavity-enhanced Raman spectroscopy (CERS) with optical feedback cw-diode lasers as a sensitive analytical tool. Here we report improvements made on the technique and its first application in the biosciences for in situ, multicomponent, and isotope selective gas measure-ments to study hydrogen production and consumption by Escherichia coli. Under anaerobic conditions, cultures grown on rich media supplemented with D-glucose or glycerol produce H 2 and simultaneously consume some of it. By introducing D 2 in the headspace, hydrogen production and consumption could be separated due to the distinct spectroscopic signatures of isotopomers. Different phases with distinctly different kinetic regimes of H 2 and CO 2 production and D 2 consumption were identified. Some of the D 2 consumed is converted back to H 2 via H/D exchange with the solvent. HD was formed only as a minor component. This reflects either that H/D exchange at hydrogenase active sites is rapid compared to the rate of recombination, rapid recapture of HD occurs after the molecule is formed, or that the active sites where D 2 oxidation and proton reduction occur are physically separated. Whereas in glucose supplemented cultures, addition of D 2 led to an increase in H 2 produced, while the yield of CO 2 remained unchanged; with glycerol, addition of D 2 led not only to increased yields of H 2 , but also significantly increased CO 2 production, reflecting an impact on fermentation pathways. Addition of CO was found to completely inhibit H 2 production and significantly reduce D 2 oxidation, indicating at least some role for O 2 -tolerant Hyd-1 in D 2 consumption.

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Accepted/In Press date: 10 January 2017
e-pub ahead of print date: 10 January 2017
Published date: 7 February 2017
Keywords: Raman, Spectroscopy, Biohydrogen

Identifiers

Local EPrints ID: 425315
URI: http://eprints.soton.ac.uk/id/eprint/425315
ISSN: 0003-2700
PURE UUID: 7499cbab-83d1-48e3-aabe-628d684ea236

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Date deposited: 12 Oct 2018 16:30
Last modified: 06 Oct 2020 22:29

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