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Wei Cong - One of the best experts on this subject based on the ideXlab platform.
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a novel Photobioreactor structure using optical fibers as inner light source to fulfill flashing light effects of microalgae
Bioresource Technology, 2013Co-Authors: Shengzhang Xue, Qinghua Zhang, Xia Wu, Chenghu Yan, Wei CongAbstract:Abstract In this work, a novel Photobioreactor structure using optical fibers being fixed vertically to culture flow direction as inner light source was proposed to fulfill flashing light effects (FLE) of microalgae, so as to obtain high light efficiency. Three types of optical-fiber Photobioreactor fulfilling FLE of microalgae, i.e. air-driven panel, pump-driven panel and stirred tank type, were proposed and a 130 L airlift panel one was practically constructed on which both cold (light profile, liquid velocity) and hot model tests were carried out. Results demonstrated that it could produce uniformed light/dark frequencies being over 10 Hz and microalgae productivity increased by 43% and 38% for Spirulina platensis and Scenedesmus dimorphus respectively, compared with the control. This suggested the structure to be a viable and promising option for future Photobioreactors.
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a novel Photobioreactor structure using optical fibers as inner light source to fulfill flashing light effects of microalgae
Bioresource Technology, 2013Co-Authors: Shengzhang Xue, Qinghua Zhang, Chenghu Yan, Wei CongAbstract:In this work, a novel Photobioreactor structure using optical fibers being fixed vertically to culture flow direction as inner light source was proposed to fulfill flashing light effects (FLE) of microalgae, so as to obtain high light efficiency. Three types of optical-fiber Photobioreactor fulfilling FLE of microalgae, i.e. air-driven panel, pump-driven panel and stirred tank type, were proposed and a 130 L airlift panel one was practically constructed on which both cold (light profile, liquid velocity) and hot model tests were carried out. Results demonstrated that it could produce uniformed light/dark frequencies being over 10 Hz and microalgae productivity increased by 43% and 38% for Spirulina platensis and Scenedesmus dimorphus respectively, compared with the control. This suggested the structure to be a viable and promising option for future Photobioreactors.
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hydrodynamic characteristics and microalgae cultivation in a novel flat plate Photobioreactor
Biotechnology Progress, 2013Co-Authors: Qing H Zhang, Sheng Z Xue, Zhi H Wang, Cheng H Yan, Wei CongAbstract:Flat-plate Photobioreactors (FPPBRs) are widely reported for cultivation of microalgae. In this work, a novel FPPBR mounted with inclined baffles was developed, which can make the fluid produce a spirality flow. The flow field and cell trajectory in the Photobioreactor were investigated by using computational fluid dynamics. In addition, the cell trajectory was analyzed using a Fast Fourier transformation. The influence of height of the baffles, the angle between the inclined baffle and fluid inlet flow direction (z), and the fluid inlet velocity on the frequency of flashing light effect and pressure drop were examined to optimize the structure parameters of the inclined baffles and operating conditions of the Photobioreactor. The results showed that with inclined baffles built-in, significant swirl flow could be generated in the FPPBR. In this way, the flashing light effect for microalgal cell could also be achieved and the photosynthesis efficiency of microalgae could be promoted. In outdoor cultivation of freshwater Chlorella sp., the maximum biomass productivity of Chlorella sp. cultivated in the Photobioreactor with inclined baffles was 29.94% higher than that of the Photobioreactor without inclined baffles. (c) 2012 American Institute of Chemical Engineers Biotechnol. Prog. 29;127-134, 2013
Sarka Moudřikova - One of the best experts on this subject based on the ideXlab platform.
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growth of algal biomass in laboratory and in large scale algal Photobioreactors in the temperate climate of western germany
Bioresource Technology, 2017Co-Authors: Christina Schreiber, Dominik Behrendt, Gregor Huber, Christian Pfaff, Janka Widzgowski, Barbel Ackermann, Andreas Muller, Vilem Zachleder, Sarka MoudřikovaAbstract:Growth of Chlorella vulgaris was characterized as a function of irradiance in a laboratory turbidostat (1L) and compared to batch growth in sunlit modules (5-25L) of the commercial NOVAgreen Photobioreactor. The effects of variable sunlight and culture density were deconvoluted by a mathematical model. The analysis showed that algal growth was light-limited due to shading by external construction elements and due to light attenuation within the algal bags. The model was also used to predict maximum biomass productivity. The manipulative experiments and the model predictions were confronted with data from a production season of three large-scale Photobioreactors: NOVAgreen (<36,000L), IGV (2,500-3,500L), and Phytolutions (28,000L). The analysis confirmed light-limitation in all three Photobioreactors. An additional limitation of the biomass productivity was caused by the nitrogen starvation that was used to induce lipid accumulation. Reduction of shading and separation of biomass and lipid production are proposed for future optimization.
René H. Wijffels - One of the best experts on this subject based on the ideXlab platform.
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Comparison of four outdoor pilot-scale Photobioreactors
Biotechnology for Biofuels, 2015Co-Authors: J. H. De Vree, Marcel Janssen, Maria J Barbosa, Rouke Bosma, René H. WijffelsAbstract:BACKGROUND: Microalgae are a potential source of sustainable commodities of fuels, chemicals and food and feed additives. The current high production costs, as a result of the low areal productivities, limit the application of microalgae in industry. A first step is determining how the different production system designs relate to each other under identical climate conditions. The productivity and photosynthetic efficiency of Nannochloropsis sp. CCAP 211/78 cultivated in four different outdoor continuously operated pilot-scale Photobioreactors under the same climatological conditions were compared. The optimal dilution rate was determined for each Photobioreactor by operation of the different Photobioreactors at different dilution rates.\n\nRESULTS: In vertical Photobioreactors, higher areal productivities and photosynthetic efficiencies, 19-24 g m(-2) day(-1) and 2.4-4.2 %, respectively, were found in comparison to the horizontal systems; 12-15 g m(-2) day(-1) and 1.5-1.8 %. The higher ground areal productivity in the vertical systems could be explained by light dilution in combination with a higher light capture. In the raceway pond low productivities were obtained, due to the long optical path in this system. Areal productivities in all systems increased with increasing photon flux densities up to a photon flux density of 30 mol m(-2) day(-1). Photosynthetic efficiencies remained constant in all systems with increasing photon flux densities. The highest photosynthetic efficiencies obtained were; 4.2 % for the vertical tubular Photobioreactor, 3.8 % for the flat panel reactor, 1.8 % for the horizontal tubular reactor, and 1.5 % for the open raceway pond.\n\nCONCLUSIONS: Vertical Photobioreactors resulted in higher areal productivities than horizontal Photobioreactors because of the lower incident photon flux densities on the reactor surface. The flat panel Photobioreactor resulted, among the vertical Photobioreactors studied, in the highest average photosynthetic efficiency, areal and volumetric productivities due to the short optical path. Photobioreactor light interception should be further optimized to maximize ground areal productivity and photosynthetic efficiency.
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photosynthetic efficiency of chlamydomonas reinhardtii in flashing light
Biotechnology and Bioengineering, 2011Co-Authors: Carsten Vejrazka, Marcel Janssen, Mathieu Streefland, René H. WijffelsAbstract:Efficient light to biomass conversion in Photobioreactors is crucial for economically feasible microalgae production processes. It has been suggested that photosynthesis is enhanced in short light path Photobioreactors by mixing-induced flashing light regimes. In this study, photosynthetic efficiency and growth of the green microalga Chlamydomonas reinhardtii were measured using LED light to simulate light/dark cycles ranging from 5 to 100?Hz at a light-dark ratio of 0.1 and a flash intensity of 1000?µmol?m-2?s-1. Light flashing at 100?Hz yielded the same photosynthetic efficiency and specific growth rate as cultivation under continuous illumination with the same time-averaged light intensity (i.e., 100?µmol?m-2?s-1). The efficiency and growth rate decreased with decreasing flash frequency. Even at 5?Hz flashing, the rate of linear electron transport during the flash was still 2.5 times higher than during maximal growth under continuous light, suggesting storage of reducing equivalents during the flash which are available during the dark period. In this way the dark reaction of photosynthesis can continue during the dark time of a light/dark cycle. Understanding photosynthetic growth in dynamic light regimes is crucial for model development to predict microalgal Photobioreactor productivities. Biotechnol. Bioeng. 2011;108: 2905–2913. © 2011 Wiley Periodicals, Inc
Moheimani, Navid R. - One of the best experts on this subject based on the ideXlab platform.
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Outdoor phycocyanin production in a standalone thermally-insulated Photobioreactor
'Elsevier BV', 2020Co-Authors: Nwoba, Emeka G., Parlevliet, David A., Laird, Damian W., Alameh Kamal, Moheimani, Navid R.Abstract:© 2020 Elsevier Ltd The operation of solar microalgal Photobioreactors requires sufficient cooling and heating to maintain reliable high productivity year-round. These operations are energy-intensive and expensive. Growth characteristics and phycocyanin production of Arthrospira platensis were investigated during the austral winter using a thermally-insulated Photobioreactor with photovoltaic panel integration for electricity generation. This was compared with a control Photobioreactor under a cycle of heating (13-hour night) and thermostat-regulated cooling, and continuously heated raceway pond. Average temperature in the photovoltaic Photobioreactor (21.0 ± 0.03 °C) was similar to that in the heated control. Biomass productivity of Arthrospira in the novel Photobioreactor was 67% higher than in the raceway pond but significantly lower than the control. Phycocyanin productivity (16.3 ± 1.43 mgg−1d−1 and purity (1.2 ± 0.03) showed no variation between Photobioreactors but was significantly lower in the raceway pond. Electrical energy output of the photovoltaic Photobioreactor exceeded mixing energy needs by 75%. These results indicate that the novel Photobioreactor offers a reliable, energy-efficient platform for large-scale production of high-value chemicals from microalgae
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Energy efficiency analysis of outdoor standalone photovoltaic-powered Photobioreactors coproducing lipid-rich algal biomass and electricity
'Elsevier BV', 2020Co-Authors: Nwoba, Emeka G., Parlevliet, David A., Laird, Damian W., Alameh Kamal, Louveau Julien, Pruvost Jeremy, Moheimani, Navid R.Abstract:© 2020 Elsevier Ltd The need for thermal regulation in microalgal Photobioreactors is a significant impediment to their large-scale adoption. The energy costs associated with thermal regulation alone can easily result in a negative energy balance. Self-sustaining photovoltaic powered Photobioreactors that do not require cooling systems provide an opportunity to maximize biomass productivity, generate local electricity, reduce thermal regulation requirements, and significantly improve the energy balance of the system. Net energy analysis of a spectrally-selective, insulated-glazed photovoltaic Photobioreactor (IGP) with an integrated capability for renewable electricity generation used to cultivate Nannochloropsis sp. without freshwater-based cooling resulted in a net energy ratio of 2.96, a figure comparable to agricultural bio-oil crops such as Jatropha and soybean. Experimental data from pilot-scale operation of this novel Photobioreactor producing Nannochloropsis biomass under outdoor conditions was extrapolated to a 1-ha IGP installation. Annual biomass productivity reached 66.0-tons dry weight ha−1, equivalent to overall energy output of 1696.2 GJ ha−1. The integrated semi-transparent photovoltaic panels generated an additional 1126.8 GJ ha−1 yr−1 (313.0 MWh ha−1 yr−1). Energy demands from plant building materials, machinery, fertilizers, plant operations, and biomass harvesting constituted total energy input with a combined value of 707.3 GJ ha−1 yr−1. Comparison with a conventional Photobioreactor requiring passive evaporative cooling showed novel Photobioreactor had a 73% greater net energy ratio. Nannochloropsis cultivation in IGP system ensured co-production of lipid and protein of 34.7 and 25.7-tons ha−1 yr−1, respectively. These results suggest that this novel Photobioreactor could be a viable and sustainable biomass production technology for mass microalgal cultivation
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Does growing Nannochloropsis sp. in innovative flat plate Photobioreactors result in changes to fatty acid and protein composition?
'Springer Science and Business Media LLC', 2020Co-Authors: Nwoba, Emeka G., Parlevliet, David A., Laird, Damian W., Alameh Kamal, Moheimani, Navid R.Abstract:© 2020, Springer Nature B.V. Solar cultivation of microalgae in Photobioreactors is a valuable bioprocess for the sustainable production of commercially useful metabolites. However, the conventional culture temperature control method in solar closed Photobioreactors of evaporative cooling is neither economical nor sustainable. In this study, a novel spectrally selective, insulated glazed flat plate (IGP) Photobioreactor employing an infrared reflecting system embedded in the illumination surface was used for cultivation of Nannochloropsis sp. The impact of the temperature control technology on protein, lipid, carbohydrate content and fatty acid profile of Nannochloropsis sp. was investigated and compared to closed Photobioreactors using passive evaporative cooling (PEC) and an infrared reflecting film (IRF) on the surface as well as an open raceway pond (ORP). Among all cultivation systems tested, the biochemical composition of biomass (mg g−1 organic biomass) showed a general trend of lipid \u3e protein \u3e carbohydrate, with no large variation of each across treatments. However, the areal and volumetric productivities of these constituents were significantly higher in the Photobioreactors than in the ORP; results consistent with biomass productivity data. Of the major saturated and monounsaturated fatty acids present, only the proportion of C16:0, which is 24% higher in the Photobioreactors than in the ORP, changed significantly among cultivation systems. The highest content of high-value dietary fatty acids, eicosapentaenoic acid (EPA, C20:5n-3; 15.5%) and ϒ-linolenic acid (C18:3n-6; 8%) were found in the ORP but were similar to that produced in the IGP (15.9 and 3.4%, respectively). Among all Photobioreactors, the IGP had the least diel temperature changes and an EPA content that was 21% higher than PEC. Photobioreactors constructed with spectrally selective materials effectively allow management of internal reactor temperature with no significant negative impact on biochemical and fatty acid profiles of microalgae
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Sustainable phycocyanin production from Arthrospira platensis using solar-control thin film coated Photobioreactor
'Elsevier BV', 2019Co-Authors: Nwoba, Emeka G., Parlevliet, David A., Laird, Damian W., Alameh Kamal, Moheimani, Navid R.Abstract:Solar irradiance consists of photosynthetically-active photons that can be transformed to valuable biomolecules by microalgae. Light also has undesirable non-photosynthetic photons, such as ultraviolet and infrared wavelengths that heat up algal closed Photobioreactors above optimum temperatures for growth. In this study, a solar control infrared blocking film (IRF) is applied to an algal flat plate Photobioreactor to block excessive non-photosynthetic photons and regulate the temperature profile of Arthrospira platensis cultures for the production of C-phycocyanin (C-PC). The performance of the IRF is compared against other cooling mechanisms such as insulated-glazed photovoltaic (IGP), conventional water-jacket (CWJ) and a no heat control (NHC) Photobioreactors. Experimental results show that the maximum temperature (30.94 ± 0.09 °C) in the IRF culture is only 5% higher than that in CWJ culture but 33% lower than that in NHC cultures. No significant differences were found in C-PC content or biomass productivity when Arthrospira is grown using IGP, CWJ or IRF but is significantly lower in NHC Photobioreactors. Chlorophyll a fluorescence probing of A. platensis shows that IRF, IGP and CWJ cultures are not thermally stressed, however, NHCs cultures are highly stressed due to supraoptimal temperatures. Our results clearly indicate that solar control film is a potential tool for blocking non-photosynthetic photons and managing culture temperature in flat plate Photobioreactors for sustainable C-phycocyanin production from A. platensis
Dongda Zhang - One of the best experts on this subject based on the ideXlab platform.
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synergising biomass growth kinetics and transport mechanisms to simulate light dark cycle effects on photo production systems
Biotechnology and Bioengineering, 2021Co-Authors: Bovinille Anye Cho, Miguel Ángel De Carvalho Servia, Ehecatl Antonio Del Rio Chanona, Robin Smith, Dongda ZhangAbstract:Light attenuation is a primary challenge limiting the upscaling of Photobioreactors for sustainable bio-production. One key to this challenge, is to model and optimise the light/dark cycles so that cells within the dark region can be frequently transferred to the light region for photosynthesis. Therefore, this study proposes the first mechanistic model to integrate the light/dark cycle effects into biomass growth kinetics. This model was initially constructed through theoretical derivation based on the intracellular reaction kinetics, and was subsequently modified by embedding a new parameter, effective light coefficient, to account for the effects of culture mixing. To generate in-silico process data, a new multiscale reactive transport modelling strategy was developed to couple fluid dynamics with biomass growth kinetics and light transmission. By comparing against previous experimental and computational studies, the multiscale model shows to be of high accuracy. Based on its simulation result, an original correlation was proposed to link effective light coefficient with Photobioreactor gas inflow rate; this has not been done before. The impact of this study is that by using the proposed mechanistic model and correlation, we can easily control and optimise Photobioreactor gas inflow rates to alleviate light attenuation and maintain a high biomass growth rate. This article is protected by copyright. All rights reserved.
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dynamic modelling of high biomass density cultivation and biohydrogen production in different scales of flat plate Photobioreactors
Biotechnology and Bioengineering, 2015Co-Authors: Dongda Zhang, Pongsathorn Dechatiwongse, Ehecatl Antonio Del Riochanona, Geoffrey C Maitland, Klaus Hellgardt, Vassilios S VassiliadisAbstract:This paper investigates the scaling-up of cyanobacterial biomass cultivation and biohydrogen production from laboratory to industrial scale. Two main aspects are investigated and presented, which to the best of our knowledge have never been addressed, namely the construction of an accurate dynamic model to simulate cyanobacterial photo-heterotrophic growth and biohydrogen production and the prediction of the maximum biomass and hydrogen production in different scales of Photobioreactors. To achieve the current goals, experimental data obtained from a laboratory experimental setup are fitted by a dynamic model. Based on the current model, two key original findings are made in this work. First, it is found that selecting low-chlorophyll mutants is an efficient way to increase both biomass concentration and hydrogen production particularly in a large scale Photobioreactor. Second, the current work proposes that the width of industrial scale Photobioreactors should not exceed 0.20 m for biomass cultivation and 0.05 m for biohydrogen production, as severe light attenuation can be induced in the reactor beyond this threshold. Biotechnol. Bioeng. 2015;112: 2429–2438. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Peiodicals, Inc.
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analysis of green algal growth via dynamic model simulation and process optimization
Biotechnology and Bioengineering, 2015Co-Authors: Dongda Zhang, Ehecatl Antonio Del Rio Chanona, Vassilios S Vassiliadis, Bojan TamburicAbstract:Chlamydomonas reinhardtii is a green microalga with the potential to generate sustainable biofuels for the future. Process simulation models are required to predict the impact of laboratory-scale growth experiments on future scaled-up system operation. Two dynamic models were constructed to simulate C. reinhardtii photo-autotrophic and photo-mixotrophic growth. A novel parameter estimation methodology was applied to determine the values of key parameters in both models, which were then verified using experimental results. The photo-mixotrophic model was used to accurately predict C. reinhardtii growth under different light intensities and in different Photobioreactor configurations. The optimal dissolved CO2 concentration for C. reinhardtii photo-autotrophic growth was determined to be 0.0643 g·L−1, and the optimal light intensity for algal growth was 47 W·m−2. Sensitivity analysis revealed that the primary factor limiting C. reinhardtii growth was its intrinsic cell decay rate rather than light attenuation, regardless of the growth mode. The photo-mixotrophic growth model was also applied to predict the maximum biomass concentration at different flat-plate Photobioreactors scales. A double-exposure-surface Photobioreactor with a lower light intensity (less than 50 W·m−2) was the best configuration for scaled-up C. reinhardtii cultivation. Three different short-term (30-day) C. reinhardtii photo-mixotrophic cultivation processes were simulated and optimised. The maximum biomass productivity was 0.053 g·L−1·hr−1, achieved under continuous Photobioreactor operation. The continuous stirred-tank reactor was the best operating mode, as it provides both the highest biomass productivity and lowest electricity cost of pump operation. Biotechnol. Bioeng. 2015;112: 2025–2039. © 2015 Wiley Periodicals, Inc.
