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Kultivace mikrořas v trubicovém fotobioreaktoru založeném na solárních koncentrátorech: distribuce světla
Sergejevová, M. ; Zaťková, I. ; Červený, J. ; Zrotalová, Kateřina ; Masojídek, Jiří
The cultivation system consists of two types of irradiance modules – vertical, lower-irradiance unit (close to ambient conditions) and roof, higher-irradiance unit (up to 3.5-times higher than ambient intensity) which are used to compare the growth and behaviour of microalgal cultures of various density at high light intensities. The aim of these experiments has been to monitor a diel course of irradiance intensity and spectral composition concentrated by Linear Fresnel lenses and the light distribution on the surface and inside cultivation tubes. As a model organism, we have used the cyanobacterium Spirulina platensis M2. Three concentration of biomass (about 0.5, 1 and 2 g L-1) have been tested. In higher-irradiance modules we also follow the induction of carotenoids synthesis
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Xantofylový cyklus u rostlin a zelených řas: jeho role ve fotosyntetickém aparátu
Masojídek, Jiří ; Kopecký, Jiří ; Koblížek, Michal ; Torzillo, G.
Light-induced conversion of violaxanthin to zeaxanthin, the so-called xanthophyll cycle serves as a major, short-term light acclimation mechanism in higher plants. The role of xanthophylls in thermal dissipation of surplus excitation energy was deduced from the linear relationship between zeaxanthin formation and the magnitude of nonphotochemical quenching. We have studied the role of the xanthophyll cycle in the adaptation of several species of green algae (Chlorella, Scenedesmus, Haematococcus, Chlorococcum, Spongiochloris) to high irradiance. The xanthophyll cycle was found functional in all tested organisms; however its contribution to nonphotochemical quenching is not as significant as in higher plants. We assume that algae rely on other dissipation mechanism(s), which operate along with the xanthophyll cycle-dependent quenching
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Metodika navrhování řasových fotobioreaktorů: matematické modelování hydrodynamického míchání a předpověď parametrů světelného režimu
Papáček, Š. ; Rálek, P. ; Kopecký, Jiří ; Masojídek, Jiří ; Štys, Dalibor ; Petera, K.
Computational fluid dynamics (CFD) and process simulation are important tools for the design and optimisation of biochemical processes. In this contribution, the photobioreactor design methodology based on CFD is proposed. A widely used CFD package (Fluent 6.1, by Fluent Inc.) performs a numerical approximation of microalgae trajectory (pathline) inside tubular photobioreactor. Consequently, prediction of the level of hydrodynamic mixing and corresponding light regime inside the photobioreactor with effective use of strong light by high-density algal culture is possible. In the first approach, the algal suspension is considered as a single-phase incompressible viscous Newtonian fluid, which fills the whole section of the photobioreactor photic zone. Coupling the cell trajectories with the corresponding light conditions, the light histories of single cells are obtained. These records contain complete information about light regime in photobioreactor. Computer simulations for various photobioreactor design parameters and operating conditions allow to establish the quantitative relation between variables representing design and operating parameters and light regime parameters. Thus the problem of optimal PBR design could be resolved.
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