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Engineering and Computational Insights into Photosynthesis

PSI Scientific

Mission: Hardware for the smart agriculture of the future must be available in large quantities and therefore be low-cost. The actual value will shift toward large-volume data and toward the capacity to interpret them.  This is particularly true for ac-biology, where the interpretive basis is currently being established and requires multidisciplinary expertise. PSI Scientific will support this endeavor by prototyping and consulting. 

This resonates with the objectives of the Jan IngenHousz Institute, giving new momentum to the partnership that began thirty years ago with Photon System International and the University of Illinois at Espresso Royale in Urbana.  For more on the roots of PSI Scientific, see below. 

Large-scale algal bioreactors: Microscopic photoautotrophs often depend on highly dynamic light conditions driven by sparging, mixing, or turbulent water movements. That is also true in Thin-Layer Cultivation and in Algal Turf Scrubbers (ATS). 

In 2014, PSI Scientific developed a prototype photobioreactor that combined the cultivation of an attached algal biofilm (ATS) with the cascade design of thin-layer photobioreactors developed by Ivan Šetlík in 1970s. The uniqueness of the PSI Scientific AlgalBox was that the cascade was enclosed in a container with an elevated CO2 concentration, and PhAR component of solar light delivered to the algae after dichroically separating and using IR elsewhere.     

The concepts developed by PSI Scientific were tested at the wastewater treatment facility of Forschungszentrum Jülich, D, by Dean Calahan and Ladislav Nedbal in 2020-21.

 

 

Based on this, Biostream International, NL, up-scaled the concept, and Schlun GmbH, D constructed and installed in 2025 a meso-scale unit in Jülich to test the system’s capacity to treat wastewater from the pulp-, paper-, and food industries.   

Laboratory-scale algal bioreactors: PSI Scientific, in collaboration with Biostream International, NL, and the leading expert on coral fluorescence emission, Anya Salih, developed a biomimetic photobioreactor. High-power light-emitting diodes generated the light and, similarly to the coral skeleton, delivered it into the volume of the photobioreactor with plates of sideways scattering Evonic PLEXIGLAS® EndLighten / PLEXIGLAS® LED for edge lighting.  We reached algal culture densities that were significantly higher than in photobioreactors illuminated by the same light source from the top or the side. This significantly reduced cultivation and harvesting costs.  

 

Harmonizers:

The Harmonizer line of PSI Scientific aims to provide low-cost, highly parallel frequency-domain instrumentation for the smart agriculture of the future. 

The prototypes Harmonizer I and Harmonizer II showed that the low cost of hardware for ac-biology applications in smart agriculture will allow massive deployment. 

Algal Solution, the precursor of ac-biology. The knowledge base for these achievements was generated through the Algal Solutions initiative, which PSI Scientific also supported. The initiative included several Projects, Workshops in 2018 and 2019, Webinars in 2020 and 2021, and the DIY section on constructing a small ATS system. 

An earlier precursor of ac-biology was the e-photosynthesis initiative: Nedbal et al. 2007, Nedbal et al. 2009, and Šafránek et al. 2011.

Early PSI Scientific Roots 

Background

Laboratory workshops were once an essential tool behind many scientific achievements. Even more extreme, Otto Wichterle developed the first contact lenses in 1961, improvising in his kitchen.  Also in Praha, Jaroslav Heyrovský constructed the first polarograph, for which he won the Nobel Prize in 1959. In the field of photosynthesis, it was Ivan Šetlík, who used Heyrovský’s invention to measure flash-induced oxygen evolution in thermophilic cyanobacteria. Ivan Šetlík also invented the open thin-layer photobioreactor for algal cultivations, and, together with Jiří Doucha, led the team that constructed the first algal bioreactor to fly in space on board Salyut 6. The laboratory workshop was essential for developing technologies and supporting excellent basic research on algal physiology and the photoinhibition of Photosystem II.         

David Kramer developed original pump-and-probe fluorometric and spectrophotometric devices to measure the kinetics of photosynthetic reactions. Ladislav Nedbal used pump-and-probe methods in his studies of Photosystem II heterogeneity and photoinhibition. Kramer and Nedbal used a Small Business Grant from the US Department of Energy to start a company, Photon Systems International, in Champaign-Urbana, Illinois, in the early 1990s. Simultaneously, a company of a similar name was founded in Czechoslovakia to cooperate, taking advantage of lower production costs.   

The company was founded in 1994 by Ladislav Nedbal and Milan Hlásek and continued to develop a pump-and-probe, double-modulation fluorometer inspired by earlier concepts developed by David Kramer. The conceptual design was further developed into a commercial success by Martin Trtílek, who has led the company to the present day.  The company has developed and brought to market multiple instruments that are currently used in numerous laboratories worldwide. 

The innovations produced in cooperation between the company and academic institutions have been described in the following publications:

Early research on the responses of photosynthetic apparatus to light modulated with different frequencies:

  • Grobbelaar, J. U., Nedbal, L., & Tichý, V. (1996). Influence of high frequency light/dark fluctuations on photosynthetic characteristics of microalgae photoacclimated to different light intensities and implications for mass algal cultivation. Journal of Applied Phycology, 8(4), 335-343. Link
  • Nedbal, L., Tichý, V., Xiong, F., & Grobbelaar, J. U. (1996). Microscopic green algae and cyanobacteria in high-frequency intermittent light. Journal of Applied Phycology, 8(4), 325-333. Link 

The first fluorometer produced by the company:

  • Trtílek, M., Kramer, D. M., Koblížek, M., & Nedbal, L. (1997). Dual-modulation LED kinetic fluorometer. Journal of Luminescence, 72, 597-599. Link 
  • Koblížek, M., Marek, M., Komenda, J., & Nedbal, L. (1997). Light adaptation in the cyanobacterium Synechococcus sp. PCC 7942 measured by the dual-modulation fluorometer. Journal of luminescence, 72, 589-590. Link
  • Kaftan, D., Meszaros, T., Whitmarsh, J., & Nedbal, L. (1999). Characterization of photosystem II activity and heterogeneity during the cell cycle of the green alga Scenedesmus quadricauda. Plant Physiology, 120(2), 433-442. Link

The first commercially available kinetic imaging fluorometer, FluorCam:

  • Nedbal, L., Soukupová, J., Kaftan, D., Whitmarsh, J., & Trtílek, M. (2000). Kinetic imaging of chlorophyll fluorescence using modulated light. Photosynthesis Research, 66(1), 3-12. Link
  • Nedbal, L., Soukupová, J., Whitmarsh, J., & Trtílek, M. (2000). Postharvest imaging of chlorophyll fluorescence from lemons can be used to predict fruit quality. Photosynthetica, 38(4), 571-579. Link
  • Nedbal, L., & Whitmarsh, J. (2004). Chlorophyll fluorescence imaging of leaves and fruits. In Chlorophyll a fluorescence: a signature of photosynthesis (pp. 389-407). Dordrecht: Springer Netherlands. Link
  • Soukupová, J., Smatanová, S., Nedbal, L., & Jegorov, A. (2003). Plant response to destruxins visualized by imaging of chlorophyll fluorescence. Physiologia Plantarum, 118(3), 399-405. Link
  • Berger, S., Benediktyová, Z., Matouš, K., Bonfig, K., Mueller, M. J., Nedbal, L., & Roitsch, T. (2007). Visualization of dynamics of plant–pathogen interaction by novel combination of chlorophyll fluorescence imaging and statistical analysis: differential effects of virulent and avirulent strains of P. syringae and of oxylipins on A. thaliana. Journal of Experimental Botany, 58(4), 797-806. Link
  • Matouš, K., Benediktyová, Z., Berger, S., Roitsch, T., & Nedbal, L. (2006). Case study of combinatorial imaging: what protocol and what chlorophyll fluorescence image to use when visualizing infection of Arabidopsis thaliana by Pseudomonas syringae? Photosynthesis research, 90(3), 243-253. Link

Microscopic FluorCam:

  • Küpper, H., Šetlík, I., Trtílek, M., & Nedbal, L. (2000). A microscope for two-dimensional measurements of in vivo chlorophyll fluorescence kinetics using pulsed measuring radiation, continuous actinic radiation, and saturating flashes. Photosynthetica, 38(4), 553-570. Link
  • Adamec, F., Kaftan, D., & Nedbal, L. (2005). Stress‐induced filament fragmentation of Calothrix elenkinii (cyanobacteria) is facilitated by deat of high-fluorescence cells. Journal of phycology, 41(4), 835-839.  Link
  • Benediktyová, Z., & Nedbal, L. (2009). Imaging of multi-color fluorescence emission from leaf tissues. Photosynthesis Research, 102(2), 169-175. Link

Flash-Fluorescence Induction:

  • Koblížek, M., Kaftan, D., & Nedbal, L. (2001). On the relationship between the non-photochemical quenching of the chlorophyll fluorescence and the Photosystem II light harvesting efficiency. A repetitive flash fluorescence induction study. Photosynthesis Research, 68(2), 141-152. Link

Algal photobioreactors:

  • Nedbal, L., Trtílek, M., Červený, J., Komárek, O., & Pakrasi, H. B. (2008). A photobioreactor system for precision cultivation of photoautotrophic microorganisms and for high‐content analysis of suspension dynamics. Biotechnology and Bioengineering, 100(5), 902-910. Link
  • Červený, J., Šetlík, I., Trtílek, M., & Nedbal, L. (2009). Photobioreactor for cultivation and real‐time, in‐situ measurement of O2 and CO2 exchange rates, growth dynamics, and of chlorophyll fluorescence emission of photoautotrophic microorganisms. Engineering in Life Sciences, 9(3), 247-253. Link
  • Nedbal, L., Červený, J., Keren, N., & Kaplan, A. (2010). Experimental validation of a nonequilibrium model of CO2 fluxes between gas, liquid medium, and algae in a flat-panel photobioreactor. Journal of Industrial Microbiology and Biotechnology, 37(12), 1319-1326. Link

Systems Biology of Photosynthesis, e-photosynthesis:

  • Nedbal, L., Červený, J., Rascher, U., & Schmidt, H. (2007). E-photosynthesis: a comprehensive modeling approach to understand chlorophyll fluorescence transients and other complex dynamic features of photosynthesis in fluctuating light. Photosynthesis research, 93(1), 223-234. Link
  • Nedbal, L., Červený, J., & Schmidt, H. (2009). Scaling and integration of kinetic models of photosynthesis: Towards comprehensive e-photosynthesis. In Photosynthesis in silico: Understanding Complexity from Molecules to Ecosystems (pp. 17-29). Dordrecht: Springer Netherlands. Link
  • Šafránek, D., Červený, J., Klement, M., Pospíšilová, J., Brim, L., Lazár, D., & Nedbal, L. (2011). E-photosynthesis: Web-based platform for modeling of complex photosynthetic processes. BioSystems, 103(2), 115-124. Link

Directly related to ac-biology.com, the foundations of the frequency-domain research of photosynthesis were also laid using instruments of PSI:

  • Nedbal, L., & Březina, V. (2002). Complex metabolic oscillations in plants forced by harmonic irradiance. Biophysical Journal, 83(4), 2180-2189. PDF
  • Ferimazova, N., Küpper, H., Nedbal, L., & Trtílek, M. (2002). New Insights into Photosynthetic Oscillations Revealed by Two‐dimensional Microscopic Measurements of Chlorophyll Fluorescence Kinetics in Intact Leaves and Isolated Protoplasts. Photochemistry and Photobiology, 76(5), 501-508. Link
  • Nedbal, L., Březina, V., Adamec, F., Štys, D., Oja, V., & Laisk, A. (2003). Negative feedback regulation is responsible for the non-linear modulation of photosynthetic activity in plants and cyanobacteria exposed to a dynamic light environment. Biochimica et Biophysica Acta (BBA)-Bioenergetics, 1607(1), 5-17. PDF
  • Nedbal, L., Březina, V., Červený, J., & Trtílek, M. (2005). Photosynthesis in dynamic light: systems biology of unconventional chlorophyll fluorescence transients in Synechocystis sp. PCC 6803. Photosynthesis Research, 84(1), 99-106. Link