1. Ladislav Nedbal Department of Biological Dynamics Institute of Systems Biology & Ecology CAS Zámek 136, 37333 Nové Hrady, Czech Republic

2. Solar biofuels from microorganisms, why not yet? 0 < (E FUEL –  E M ) / m 2.year = (  E  E solar - E M ) / m 2.year E M …construction, maintenance, fertilizers, pumping, harvesting, processing, refining, distribution…) E M … biological and technological constraint (≈ € !!!) E solar … geographical constraint CROPCornSoybeanCanolaJatrophaCoconutOil palmMicroalgae OIL YIELD (l/ha) 172446119018922689595013690058700 70% and 30% oil in wet biomass (adapted from Y.Chisti (2007) Biotechnology Advances 25: 294-306) RegionSW USANE USAUK Lipid content0.50.330.50.330.50.33 Biodiesel, gal/m 2 /year 1.240.821.060.710.770.52 With yields ≈ 1-2 gal(oil) / m 2 / year and oil price < $3 / gal: the capital cost depreciation < several $ / year

3. Solar biofuels from microorganisms … continued … 0 < (E FUEL –  E M ) / m 2.year = (  E  E solar - E M ) / m 2.year E M …construction, maintenance, fertilizers, pumping, harvesting, processing, refining, distribution…) E M … biological and technological constraint (≈ € !!!) E solar … geographical constraint  E … thermodynamic, biological a technological constraint Irradiance CO 2 assimilation Used Lost Solutions: - Decrease the antenna - Dilute the light technologically in space - Dilute the light technologically in time

4. High density algal cultures

5. Cell light dynamics in dense algal cultures

6. Light dynamics in dense algal cultures A. B. C.

7. Constant mean irradiance, variable period & L:D ratio B Chlorella vulgaris 500  E.m -2.s -1

8. Constant incident irradiance, variable period & L:D ratio A Chlorella vulgaris I 0 =2000  E.m -2.s -1 1ms continuous 100ms 1s

9. Constant incident irradiance, variable L:D ratio A Chlorella vulgaris 10 ms period 2400  E.m -2.s -1 1200 700 250 130

10. Constant incident irradiance, constant L:D, variable period Chlorella vulgaris L:D=1:1, I 0 =2000  E.m -2.s -1 2400  E.m -2.s -1 1200 700 250 130 T

11. Rate of photoinhibition L:D=1:1, I 0 =2000  E.m -2.s -1 T= 10ms Cont. I 0 =1000  E.m -2.s -1

12. Electron transfer

13. Conclusions for flashing light effect in the ms-range: 1) per area yield increase in dense cultures & high irradiance 2) reduction of photoinhibition rates

15. Harmonic light forcing with periods > 1 s harmonic light input non-linear output 2 amplitude T offset

16. Simulation tool Nedbal et al.(2008) Biotechnology & Bioengineering 100: 902-910.

17. Non-linear fluorescence response Continuous lightOscillating light Nedbal et al. (2003) Biochim.Biophys.Acta: Bioenergetics 1607: 5-17 Nedbal, et al. (2005) Photosynth.Res. 84: 99–106

18. Non-linear response in dynamic light

19. Non-linear response caused by regulation

22. Non-linear response in growth Constant light T=10s T=100s Constant light

24. Metabolic rhythms of the cyanobacterium Cyanothece sp. ATCC 51142 correlate with modeled dynamics of circadian clock.

25. Different L/D ratio.

27. Model prediction for circadian Kai clock confronted with metabolic dynamics in 12L: 12D

28. Model prediction for circadian Kai clock in 6L: 6D

29. Model prediction in 6L: 6D qualitatively confirmed by experiment

30. Modeling Tools

31. Models are able to simulate the non-linearity … poorly

32. Comprehensive modeling space, SBML, MIRIAM

33. …. soon to be continued

34. Thank you for your attention! Collaborators: Photon Systems Instruments, Brno, CZ Jan Červený, Ondra Komárek, Víťa Březina from Nové Hrady, CZ Fusheng Xiong, Vláďa Tichý from Třeboň, CZ Johann Grobbelaar, UOFS Bloemfontain, S.Africa Himadri Pakrasi, WUSTL, St.Louis, USA Govindjee, UIUC, Urbana, USA Agu Laisk, Tartu, Estonia Conrad Mullineaux, London, UK