Open thin-layer cascade reactors for saline microalgae production evaluated in a physically simulated Mediterranean summer climate

Apel, Andreas Christoph; Pfaffinger, Christina Evi; Basedahl, N.; Mittwollen, N.; Göbel, J.; Sauter, J.; Brück, Thomas; Weuster‐Botz, Dirk

doi:10.1016/j.algal.2017.06.004

Cited by 71 publications

(65 citation statements)

References 26 publications

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“…Algae culture densities achieved in this controlled environment are more consistent and considerably higher than those achieved in ORP systems – up from 16 g −2 day −1 (0.1 g L −1 day −1 ) to 1250 g −2 day −1 (5 g L −1 day −1 ), a factor of 50. The productivity of this design is consistent with the high‐density productivity described by Apel et al at 4 g L −1 day −1 . Apel et al report having attained algal cell densities of up to 67 g L −1 .…”

Section: Methodssupporting

confidence: 89%

Development of cost models of algae production in a cold climate using different production systems

Pankratz

Oyedun

Kumar

2019

Biofuels Bioprod Bioref

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Research into the potential use of microalgae to produce biofuels is receiving significant attention. In the cold climates of countries like Canada, algae cultivation in open raceway pond (ORP) systems is limited to a short period of the year when pond surface water temperatures and ambient light conditions enable optimal culture growth. In this study we develop techno-economic assessment models to predict, evaluate, and compare the techno-economic results from three autotrophic algae cultivation scenarios to produce algae biomass. The first is a modeled ORP site located in the southern USA, which has a minimum biomass selling price (MBSP) for algae of $541 tonne −1 (T −1 ). The second scenario models an identical ORP system co-located at a site near Fort Saskatchewan, a northern city in the province of Alberta, Canada. The resulting MBSP is $1288 T −1 . A third scenario models a photobioreactor (PBR) cultivation system co-located at the same northern Alberta site and shows algae production with an MBSP of $550 T −1 . Each system is scaled to produce 2000 T day −1 ash-free dry weight (AFDE) algae biomass. The study concludes that PBR systems deployed at this scale have the potential to reduce production costs significantly ($ T −1 ) compared to similarly sited ORP systems in Canada, despite climatic factors and high initial capital costs associated with PBR construction. Furthermore, the modeled PBR system required 0.3% of the water required by the ORP cultivation platforms (153 × 10 3 versus 59 527 × 10 3 m 3 ) and 0.04% of the land (32 versus. 82 038 ha).

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Section: Methodssupporting

confidence: 89%

Development of cost models of algae production in a cold climate using different production systems

Pankratz

Oyedun

Kumar

2019

Biofuels Bioprod Bioref

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“…In order to confirm the accuracy of the applied model, the results of this study were compared with the experimental results of [11]. The results of this study were in reasonable agreement with the experimental results, thereby verifying the present numerical methodology.…”

Section: Resultssupporting

confidence: 70%

“…A three-dimensional TLC reactor as described by [11] was used in this study. The reactor had a channel length (L) of 4 m and a channel width (W) of 1 m (Figure 1).…”

Section: Tlc Description and Mathematical Modelingmentioning

confidence: 99%

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Complete Evaluation of Cell Mixing and Hydrodynamic Performance of Thin-Layer Cascade Reactor

2020

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Microalgae are a great source of food and supplements as well as a potential source for the production of biofuels. However, the operational cost must be reduced to allow viable productions of bulk chemicals such as biofuels from microalgae. One approach to minimize the cost is to increase the efficiency of the photobioreactor. Photobioreactor efficiency is correlated to hydrodynamic mixing, which promotes single cell exposure to sunlight, keeps algae cells in suspension, and homogenizes the distribution of nutrients. Thus, a possible route to enhance the efficiency of the photobioreactor can be identified through an improved understanding of the mixing phenomenon. Therefore, for the current thin-layer cascade reactor, two aspects of its performance—namely, cell mixing and hydrodynamic characteristics—are evaluated under varying mass flow rates, slope angles, water depths, and aspect ratios of the channel by using computational fluid dynamics. The resulting model is validated with experimental data. Results reveal that limited cell mixing is achieved in the thin-layer cascade reactor with increased water depth and large aspect ratios. However, cell mixing is significantly increased at high mass flow rates. The increase in the mass flow rate and slope angle results in increased flow velocity and power consumption.

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“…The cultivation of cyanobacteria at cell densities of up to 50 g CDW L −1 is possible using systems with enhanced CO 2 and light supply . With the reaction system developed in this study (39 U g CDW −1 ), such a cell concentration would already enable a Col productivity of ≈12 g L −1 h −1 .…”

Section: Discussionmentioning

confidence: 97%

Light‐Dependent and Aeration‐Independent Gram‐Scale Hydroxylation of Cyclohexane to Cyclohexanol by CYP450 Harboring Synechocystis sp. PCC 6803

Hoschek

Toepel

Hochkeppel

et al. 2019

Biotechnology Journal

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Oxygenase‐containing cyanobacteria constitute promising whole‐cell biocatalysts for oxyfunctionalization reactions. Photosynthetic water oxidation thereby delivers the required cosubstrates, that is activated reduction equivalents and O2, sustainably. A recombinant Synechocystis sp. PCC 6803 strain showing unprecedentedly high photosynthesis‐driven oxyfunctionalization activities is developed, and its technical applicability is evaluated. The cells functionally synthesize a heterologous cytochrome P450 monooxygenase enabling cyclohexane hydroxylation. The biocatalyst‐specific reaction rate is found to be light‐dependent, reaching 26.3 ± 0.6 U gCDW−1 (U = μmol min−1 and cell dry weight [CDW]) at a light intensity of 150 µmolphotons m−2 s−1. In situ substrate supply via a two‐liquid phase system increases the initial specific activity to 39.2 ± 0.7 U gCDW−1 and stabilizes the biotransformation by preventing cell toxification. This results in a tenfold increased specific product yield of 4.5 gcyclohexanol gCDW−1 as compared to the single aqueous phase system. Subsequently, the biotransformation is scaled from a shake flask to a 3 L stirred‐tank photobioreactor setup. In situ O2 generation via photosynthetic water oxidation allows a nonaerated process operation, thus circumventing substrate evaporation as the most critical factor limiting the process performance and stability. This study for the first time exemplifies the technical applicability of cyanobacteria for aeration‐independent light‐driven oxyfunctionalization reactions involving highly toxic and volatile substrates.

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Open thin-layer cascade reactors for saline microalgae production evaluated in a physically simulated Mediterranean summer climate

Cited by 71 publications

References 26 publications

Development of cost models of algae production in a cold climate using different production systems

Development of cost models of algae production in a cold climate using different production systems

Complete Evaluation of Cell Mixing and Hydrodynamic Performance of Thin-Layer Cascade Reactor

Light‐Dependent and Aeration‐Independent Gram‐Scale Hydroxylation of Cyclohexane to Cyclohexanol by CYP450 Harboring Synechocystis sp. PCC 6803

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