Photobioreactor with ideal light–dark cycle designed and built from mathematical modeling and CFD simulation

Li, Ming; Hu, Dawei; Liu, Hong

doi:10.1016/j.ecoleng.2014.09.010

“…As to the sparger, since a single gas phase exists, we modelled the fluid dynamic variables trends accounting only for the terms of the ( Eq. (1) ) related to the gas phase, which is expressed by the following equation: Regarding the momentum balance equations, we adopted the Navier–Stokes model for the liquid–gas multiphase system, by using the following formulation ( Li, Hu & Liu, 2014 ) where p is the pressure, g is the gravity acceleration vector, τ is the stress tensor and μ is the effective viscosity. For the single-phase sparger model, the momentum balance equations are similar to Eq.…”

Section: Methodsmentioning

confidence: 99%

Analysis of the light intensity dependence of the growth ofSynechocystisand of the light distribution in a photobioreactor energized by 635 nm light

Cordara

¹

,

Re

²

,

Pagliano

³

et al. 2018

PeerJ

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Synechocystis gathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation. Synechocystis physiology and metabolism, and consequently, the productivity of Synechocystis-based photobioreactors (PBRs), are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange–red light intensities on Synechocystis growth characteristics and photosynthetic activity. Synechocystis growth and photosynthetic activity were found to raise as supplied light intensity increased up to 500 μmol photons m−2 s−1 and to enter the photoinhibition state only at 800 μmol photons m−2 s−1. Interestingly, reverting the light to a non-photo-inhibiting intensity unveiled Synechocystis to be able to promptly recover. Furthermore, our characterization displayed a clear correlation between variations in growth rate and cell size, extending a phenomenon previously observed in other cyanobacteria. Further, we applied a modelling approach to simulate the effects produced by varying the incident light intensity on its local distribution within the PBR vessel. Our model simulations suggested that the photosynthetic activity of Synechocystis could be enhanced by finely regulating the intensity of the light incident on the PBR in order to prevent cells from experiencing light-induced stress and induce their exploitation of areas of different local light intensity formed in the vessel. In the latter case, the heterogeneous distribution of the local light intensity would allow Synechocystis for an optimized usage of light.

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“…Hence, having as a tool the CFD mathematics in the frame of system analysis theory, one is able to simulate many complex hydrodynamic conditions and coupling them with microalgae kinetics to create a new most advanced PBRs geometry (see Figure ). As an excellent illustration of this approach is a work of authors . Their goal was to create a most advanced flat plate PBR (FP‐PBR) geometry, which will fulfill the most rigorous requirements for FP‐PBR such as: High surface area to volume ratio for the illumination; Achieving higher light/dark cycle frequency, preferably close to 1 Hz; Improving the overall hydrodynamics so that the issues of settling are overcome with minimum mixing energy. …”

Section: Hydrodynamics As a Sub‐systemmentioning

confidence: 99%

“…Hence, having as a tool the CFD mathematics in the frame of system analysis theory, one is able to simulate many complex hydrodynamic conditions and coupling them with microalgae kinetics to create a new most advanced PBRs geometry (see Figure 1). As an excellent illustration of this approach is a work of authors [88]. Their goal was to create a most advanced flat plate PBR (FP-PBR) geometry, which will fulfill the most rigorous requirements for FP-PBR such as:…”

Section: Hydrodynamics As a Sub-systemmentioning

confidence: 99%

Complex mathematical analysis of photobioreactor system

Scheufele

¹

,

Hinterholz

²

,

Zaharieva

³

et al. 2018

Engineering in Life Sciences

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Modeling as a tool solves extremely difficult tasks in life sciences. Recently, schemes of culturing of microalgae have received special attention because of its unique features and possible uses in many industrial applications for renewable energy production and high value products isolation. The goal of this review is to present the use of system analysis theory applied to microalgae culturing modeling and process development. The review mainly focuses on the modeling of the key steps of autotrophic growth under the integral biorefinery concept of the microalgae biomass. The system approach follows systematically a procedure showing the difficulties by modeling of sub‐systems. The development of microalgae kinetics and computational fluid dynamics (CFD) studies were analyzed in details as sub‐systems in advanced design of photobioreactor (PBR). This review logically follows the trends of the modeling procedure and clarifies how this approach may save time and money during the research efforts. The result of this work is a successful development of a complex PBR mathematical analysis in the frame of the integral biorefinery concept.

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“…Regarding the momentum balance equations, we adopted the Navier-Stokes model for the liquid-gas multiphase system, by using the following formulation (Li, Hu & Liu, 2014)…”

Section: Fluid-dynamic Equationsmentioning

confidence: 99%

Peer Review #1 of "Analysis of the light intensity dependence of the growth of Synechocystis and of the light distribution in a photobioreactor energized by 635 nm light (v0.1)"

2018

0

View full text Add to dashboard Cite

Synechocystis gathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation. Synechocystis physiology and metabolism, and consequently, the productivity of Synechocystis-based photobioreactors, are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange-red light intensities on Synechocystis growth characteristics and photosynthetic activity. Synechocystis growth and photosynthetic activity were found to raise as supplied light intensity increased up to 500 µmol photons m -2 s -1 and to enter the photoinhibition state only at 800 µmol photons Manuscript to be reviewed 47In the latter case, the heterogeneous distribution of the local light intensity would allow 48Synechocystis for an optimized usage of light.

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Photobioreactor with ideal light–dark cycle designed and built from mathematical modeling and CFD simulation

Cited by 29 publications

References 22 publications

Analysis of the light intensity dependence of the growth ofSynechocystisand of the light distribution in a photobioreactor energized by 635 nm light

Analysis of the light intensity dependence of the growth ofSynechocystisand of the light distribution in a photobioreactor energized by 635 nm light

Complex mathematical analysis of photobioreactor system

Peer Review #1 of "Analysis of the light intensity dependence of the growth of Synechocystis and of the light distribution in a photobioreactor energized by 635 nm light (v0.1)"

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