title: 13C-Labeling the carbon-fixation pathway of a highly efficient artificial photosynthetic system.
abstract: Interfacing the CO2-fixing microorganism, Ralstonia eutropha, to the energy derived from hydrogen produced by water splitting is a viable approach to achieving renewable CO2reduction at high efficiencies. We employ13C-labeling to report on the nature of CO2reduction in the inorganic water splitting|R. eutropha hybrid system. Accumulated biomass in a reactor under a13C-enriched CO2atmosphere may be sampled at different time points during CO2reduction. Converting the sampled biomass into gaseous CO2allows the13C/12C ratio to be determined by gas chromatography-mass spectrometry. After 2 hours of inoculation and the initiation of water splitting, the microbes adapted and began to convert CO2into biomass. The observed time evolution of the13C/12C ratio in accumulated biomass is consistent with a Monod model for carbon fixation. Carbon dioxide produced by catabolism was found to be minimal. This rapid response of the bacteria to a hydrogen input and to subsequent CO2reduction at high efficiency are beneficial to achieving artificial photosynthesis for the storage of renewable energy.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA. dnocera@fas.harvard.edu.
authors.forename: Chong
authors.initials: C
authors.lastname: Liu
authors.forename: Shannon N
authors.initials: SN
authors.lastname: Nangle
authors.forename: Brendan C
authors.initials: BC
authors.lastname: Colón
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Silver
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Nocera