Towards a quantitative assessment of inorganic carbon cycling in photosynthetic microorganisms

0510250 - ÚVGZ 2020 RIV DE eng J - Journal Article
Müller, S. - Zavřel, Tomáš - Červený, Jan
Towards a quantitative assessment of inorganic carbon cycling in photosynthetic microorganisms.
Engineering in Life Sciences. Roč. 19, č. 10 (2019), s. 1-13. ISSN 1618-0240. E-ISSN 1618-2863
R&D Projects: GA MŠMT(CZ) LO1415
Research Infrastructure: CzeCOS II - 90061
Institutional support: RVO:86652079
Keywords : carbonate chemistry * computational modeling * cyanobacteria * futile cycles * photosynthesis
OECD category: Plant sciences, botany
Impact factor: 1.934, year: 2019
Method of publishing: Open access
https://onlinelibrary.wiley.com/doi/full/10.1002/elsc.201900061

Photosynthetic organisms developed various strategies to mitigate high light stress. For instance, aquatic organisms are able to spend excessive energy by exchanging dissolved carbon dioxide (dCO2) and bicarbonate (HCO3-) with the environment. Simultaneous uptake and excretion of the two carbon species is referred to as inorganic carbon cycling (ICC). Often, ICC is indicated by displacements of the extracellular dCO2 signal from the equilibrium value after changing the light conditions. In this work, we additionally use (i) the extracellular pH signal, which requires non- or weakly-buffered medium, and (ii) a dynamic model of carbonate chemistry in the aquatic environment in order to detect and quantitatively describe ICC. Based on simulations and experiments in precisely controlled photobioreactors, we show that the magnitude of the observed dCO2 displacement crucially depends on extracellular pH level and buffer concentration. Moreover, we find that the dCO2 displacement can also be caused by simultaneous uptake of both dCO2 and HCO3- (no ICC). In a next step, the dynamic model of carbonate chemistry allows for a quantitative assessment of cellular dCO2 , HCO3- , and H+ exchange rates from the measured dCO2 and pH signals. Limitations of the method are discussed.
Permanent Link: http://hdl.handle.net/11104/0301002