Shedding light on blue-green photosynthesis: A wavelength-dependent mathematical model of photosynthesis in Synechocystis sp. PCC 6803
Fig 5
In silico analysis of biotechnological compound production.
A: Monochromatic lights used in the analysis (Gaussian LED, σ = 0.001) shown as colored spikes. Relative absorption spectra of selected pigments are shown in the background. B-D: Simulated production capacities of biotechnological compounds under light variation. We created three models, each containing a sink reaction consuming energy carriers in the ratio corresponding to a biotechnological target compound, including the cost of carbon fixation. The models were simulated to steady-state under illumination with varying intensity of the lights in A. We disabled the CBB reaction and limited ATP and NADPH concentrations to 95% of their total pools. Thus we estimate the maximal production rate of energy carriers in a desired ratio, assuming optimal carbon assimilation for the process and no product inhibition. The shown sinks represent pure NADPH extraction (B), production of terpenes (C; 19 ATP, 11 NADPH, 4 Fdred), and sucrose (D; 19 ATP, 12 NADPH). E,F: Comparison of measured isoprene production and simulated production capacity under light variation. We show the growth and isoprene production rates measured under monochromatic illuminations (405 nm, 450 nm, 540 nm and 630 nm at 50 (E) or 100 μmol(photons) m−2 s−1 (F)) by Rodrigues et al. [29]. The model was adapted to the measured pigment composition (see Table D in S1 Appendix) and simulated to steady-state under the respective monochromatic lights. We implemented the sink reaction representing isoprene as in C.