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

Ladislav NedbalDepartment of Biological Dynamics

Institute of Systems Biology & Ecology CASZámek 136, 37333 Nové Hrady, Czech Republic

Solar biofuels from microorganisms, why not yet?

0 < (EFUEL –EM) / m2.year = (EEsolar - EM) / m2.yearEM… construction, maintenance, fertilizers, pumping, harvesting,

processing, refining, distribution…)

EM … biological and technological constraint (≈ € !!!)

Esolar … geographical constraint

CROP Corn Soybean Canola Jatropha Coconut Oil palm Microalgae Microalgae

OIL YIELD (l/ha)

172 446 1190 1892 2689 5950 136900 58700

70% and 30% oil in wet biomass (adapted from Y.Chisti (2007) Biotechnology Advances 25: 294-306)

Region SW USA NE USA UK

Lipid content 0.5 0.33 0.5 0.33 0.5 0.33

Biodiesel, gal/m2/year

1.24 0.82 1.06 0.71 0.77 0.52

With yields ≈ 1-2 gal(oil) / m2 / year and oil price < $3 / gal: the capital cost depreciation < several $ / year

Solar biofuels from microorganisms … continued …0 < (EFUEL –EM) / m2.year = (EEsolar - EM) / m2.year

EM… construction, maintenance, fertilizers, pumping, harvesting, processing, refining, distribution…)

EM … biological and technological constraint (≈ € !!!)Esolar … geographical constraint

E … thermodynamic, biological a technological constraint

Irradiance

Used

LostSolutions:- Decrease the antenna- Dilute the light technologically in space

- Dilute the light technologically in time

High density algal cultures

Cell light dynamics in dense algal cultures

Light dynamics in dense algal cultures

A.A.

B.B.

C.C.

Constant mean irradiance, variable period & L:D ratio

BB

Chlorella vulgaris500 E.m-2.s-1

Constant incident irradiance, variable period & L:D ratio

AA

Chlorella vulgarisI0=2000 E.m-2.s-1

1ms

continuous

100ms

1s

Constant incident irradiance, variable L:D ratio

AA

Chlorella vulgaris10 ms period

2400 E.m-2.s-1

1200

700

250

130

Constant incident irradiance, constant L:D, variable period

Chlorella vulgarisL:D=1:1, I0=2000 E.m-2.s-1

2400 E.m-2.s-1

1200

700

250

130

T

Rate of photoinhibition

L:D=1:1, I0=2000 E.m-2.s-1

T= 10ms

Cont. I0=1000 E.m-2.s-1

Electron transfer

Conclusions for flashing light effect in the ms-range:

1) per area yield increase in dense cultures & high irradiance

2) reduction of photoinhibition rates

Harmonic light forcing with periods > 1 s

harmonic light input

non-linear output

2 amplitudeT

offset

Simulation tool

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

Non-linear fluorescence responseContinuous light Oscillating light

Nedbal et al. (2003) Biochim.Biophys.Acta: Bioenergetics 1607: 5-17Nedbal, et al. (2005) Photosynth.Res. 84: 99–106

Non-linear response in dynamic light

Non-linear response caused by regulation

Non-linear response caused by regulation

Non-linear response caused by regulation

Non-linear response in growth C

onst

ant l

ight

T=10

s

T=10

0s

Con

stan

t lig

ht

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

Different L/D ratio.

Different L/D ratio.

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

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

Model prediction in 6L: 6D qualitatively confirmedby experiment

Modeling Tools

Models are able to simulate the non-linearity … poorly

Comprehensive modeling space, SBML, MIRIAM

…. soon to be continued

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