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Policastro G, Ebrahimi S, Weissbrodt DG, Fabbricino M, van Loosdrecht MCM. Selecting for a high lipid accumulating microalgae culture by dual growth limitation in a continuous bioreactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169213. [PMID: 38097066 DOI: 10.1016/j.scitotenv.2023.169213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 12/25/2023]
Abstract
A dual-growth-limited continuous operated bioreactor (chemostat) was used to enhance lipid accumulation in an enrichment culture of microalgae. The light intensity and nitrogen concentration where both limiting factors resulting in high lipid accumulation in the mixed culture. Both conditions of light and nitrogen excess and deficiency were tested. Strategies to selectively enrich for a phototrophic lipid-storing community, based on the use of different nitrogen sources (ammonium vs. nitrate) and vitamin B supplementation in the growth medium, were evaluated. The dual limitation of both nitrogen and light enhanced the accumulation of storage compounds. Ammoniacal nitrogen was the preferred nitrogen source. Vitamin B supplementation led to a doubling of the lipid productivity. The availability of vitamins played a key role in selecting an efficient lipid-storing community, primarily consisting of Trebouxiophyceae (with an 82 % relative abundance among eukaryotic microorganisms). The obtained lipid volumetric productivity (387 mg L-1 d-1) was among the highest reported in literature for microalgae bioreactors. Lipid production by the microalgae enrichment surpassed the efficiencies reported for continuous microalgae pure cultures, highlighting the benefits of mixed-culture photo-biotechnologies for fuels and food ingredients in the circular economy.
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Affiliation(s)
- Grazia Policastro
- Department of Engineering and Computer Science, Telematic University Pegaso, Naples, Italy; Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Naples, Italy.
| | - Sirous Ebrahimi
- Biotechnology Research Center, Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran; Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
| | - David G Weissbrodt
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands; Department of Biotechnology and Natural Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Massimiliano Fabbricino
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Naples, Italy
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Li X, Jiang M, Lv C, Xie B. Theoretical and experimental study on the radiative properties of Parachlorella kessleri: considering the effect of internal microstructure. APPLIED OPTICS 2024; 63:1330-1339. [PMID: 38437313 DOI: 10.1364/ao.511731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 01/17/2024] [Indexed: 03/06/2024]
Abstract
A microalgal cell model with multiple organelles considering both the irregular overall shape and internal microstructure was proposed. The radiative properties of Parachlorella kessleri during the normal phase, starch-rich phase, and lipid-rich phase were calculated by the discrete dipole approximation method in the visible wavelengths. The accuracy of the model is verified with experimental measurements. The results showed that the theoretical calculation of the established microalgal cell model is more accurate than those of the equal volume spheres, such as the homogeneous sphere and the coated sphere, with the errors of the scattering cross-section reduced by more than 10.7%. The calculated scattering phase function of the multi-component model is basically in good agreement with the experimental results. Compared to the normal growth phase, the lipid enrichment during the lipid-rich phase leads to a sharp increase in the scattering cross-section by three to four times, while the absorption cross-section remains stable. Remarkably, in the starch-rich phase, the abundant production of starch results in a reduction of two to three times in the absorption cross-section compared to the normal growth phase, while the scattering cross-section varies little. The results can provide basic data and theoretical support for the design and optimization of photobioreactors.
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Samhat K, Kazbar A, Takache H, Ismail A, Pruvost J. Influence of light absorption rate on the astaxanthin production by the microalga Haematococcus pluvialis during nitrogen starvation. BIORESOUR BIOPROCESS 2023; 10:78. [PMID: 38647902 PMCID: PMC10992552 DOI: 10.1186/s40643-023-00700-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/24/2023] [Indexed: 04/25/2024] Open
Abstract
Large amounts of astaxanthin (about 4% DW) can be produced under nitrogen starvation of Haematococcus pluvialis in photobioreactors (PBRs) exposed to high light conditions to induce a light stress. However, in PBR, the large biomass concentration usually achieved leads to strong light attenuation conditions, which makes complex the analysis of this "light stress". This study aims to elucidate the role of light transfer in astaxanthin cell content and productivity from the microalga Haematococcus pluvialis during nitrogen starvation. Haematococcus pluvialis was cultivated in a flat-panel PBR in a batch mode with sudden nitrogen starvation conditions and an incident photon flux density (PFD) of 250 µmolhν m-2 s-1. Different initial biomass concentrations ( C x 0 ) were evaluated, 0.21, 0.52, 1.39 and 2.21 kg m-3. As a result, spectral mass absorption cross-sections of Haematococcus pluvialis were measured at different times during nitrogen starvation, and were used to relate the mean rate of photon absorption (MRPA) to the astaxanthin productivity. A minimum initial MRPA of 7000 ± 500 µmolhν kgx-1 s-1 was found necessary to trigger large accumulation of astaxanthin in Haematococcus pluvialis cells (up to 3.21% DW) during nitrogen starvation conditions. The results also demonstrated the link between the MRPA and the daily astaxanthin productivity of Haematococcus pluvialis cultures, introducing then the MRPA as a physical quantity of interest for a rational optimization of the light culture conditions in PBRs.
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Affiliation(s)
- Khadija Samhat
- Oniris, CNRS, GEPEA, UMR 6144, Nantes University, 44600, Saint-Nazaire, France.
- Platform for Research and Analysis in Environmental Sciences, Doctoral School of Science and Technology, Lebanese University, Rafic Hariri Campus, Beirut, Lebanon.
| | - Antoinette Kazbar
- Algosource, 7 Rue Eugène Cornet, 44600, Saint-Nazaire, France
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - Hosni Takache
- Bio-Information Research Laboratory (BIRL), The Higher Institute of Biotechnologies of Paris (Sup'biotech), 66 Rue Guy Môquet, 94800, Villejuif, France
| | - Ali Ismail
- Platform for Research and Analysis in Environmental Sciences, Doctoral School of Science and Technology, Lebanese University, Rafic Hariri Campus, Beirut, Lebanon
| | - Jeremy Pruvost
- Oniris, CNRS, GEPEA, UMR 6144, Nantes University, 44600, Saint-Nazaire, France
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Heredia V, Marchal L, Gonçalves O, Pruvost J. Optimization of continuous TAG production by Nannochloropsis gaditana in solar-nitrogen-limited culture. Biotechnol Bioeng 2022; 119:1808-1819. [PMID: 35377482 DOI: 10.1002/bit.28097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 11/08/2022]
Abstract
Nitrogen limitation and changing solar conditions are both known to affect triacylglycerol (TAG) production in microalgae. This work investigates the optimization of TAG production with a continuous nitrogen-limited culture of Nannochloropsis gaditana in simulated day-night cycles. The effect of day-night cycles was firstly investigated in nitrogen-deprived condition (i.e. batch culture), emphasizing a significant change in mechanical resistance of the strain during the night. The concept of Released TAG, which shows how much of the TAG produced is actually recovered in the downstream stages, i.e. after cell disruption, was shown here of interest. For a maximum released TAG, the optimum harvesting time was suggested as being 4 hours into the night period, which minimizes the losses due to a too great cell mechanical resistance. The protocol for continuous nitrogen-limited culture was then optimized, and a continuous nitrogen addition was compared to a pulsed-addition. For the latter, nitrogen was supplied in a single pulse at the beginning of the light periods, while the bulk medium was supplied separately at a slow but constant dilution rate of 0.005 h - 1 . The pulse dose was calculated after the study of nitrogen consumption and TAG production/consumption during the day-night cycles. The estimated released TAG for the pulsed-addition of 1.4 ⋅ 1 0 - 3 kg/m 2 ⋅ d was found significantly higher than the one achieved in batch culture (0.3 ⋅ 1 0 - 3 kg/m 2 ⋅ d) but lower than for continuous nitrogen addition which obtained the highest released TAG of 3 ⋅ 1 0 - 3 kg/m 2 ⋅ d. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Vladimir Heredia
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Luc Marchal
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Olivier Gonçalves
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Jeremy Pruvost
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
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Liu S, Rouquié C, Lavenant L, Frappart M, Couallier E. Coupling bead-milling and microfiltration for the recovery of lipids and proteins from Parachlorella kessleri: Impact of the cell disruption conditions on the separation performances. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Xi Y, Xue S, Cao X, Chi Z, Wang J. Quantitative analysis on photon numbers received per cell for triggering β-carotene accumulation in Dunaliella salina. BIORESOUR BIOPROCESS 2021; 8:104. [PMID: 38650246 PMCID: PMC10992135 DOI: 10.1186/s40643-021-00457-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/10/2021] [Indexed: 11/10/2022] Open
Abstract
Accumulation of β-carotene in Dunaliella salina is highly dependent on light exposure intensity and duration, but quantitative analysis on photon numbers received per cell for triggering β-carotene accumulation is not available so far. In this study, experiment results showed that significant β-carotene accumulation occurred after at least 8 h illumination at 400 µmol photons·m-2·s-1. To quantify the average number of photons received per cell, correlations of light attenuation with light path, biomass concentration, and β-carotene content were, respectively, established using both Lambert-Beer and Cornet models, and the latter provided better simulation. Using Cornet model, average number of photons received per cell (APRPC) was calculated and proposed as a parameter for β-carotene accumulation, and constant APRPC was maintained by adjusting average irradiance based on cell concentration and carotenoids content changes during the whole induction period. It was found that once APRPC reached 0.7 µmol photons cell-1, β-carotene accumulation was triggered, and it was saturated at 9.9 µmol photons cell-1. This study showed that APRPC can be used as an important parameter to precisely simulate and control β-carotene production by D. salina.
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Affiliation(s)
- Yimei Xi
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China
| | - Song Xue
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China
| | - Xupeng Cao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 16023, China
| | - Zhanyou Chi
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
| | - Jinghan Wang
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China.
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Producing Energy-Rich Microalgae Biomass for Liquid Biofuels: Influence of Strain Selection and Culture Conditions. ENERGIES 2021. [DOI: 10.3390/en14051246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day–night cycles: Nannochloropsis gaditana, a seawater species, and Parachlorella kessleri, a freshwater species. Lipid and carbohydrate production are investigated, as well as cell resistance to mechanical disruption for energy-rich compound release. Nitrogen-depleted N. gaditana showed only a low consumption of energy-storage molecules with a non-significant preference for neutral lipids (TAG) and carbohydrates in day–night cycles. However, it did accumulate significantly fewer carbohydrates than P. kessleri. Following this, the highest levels of productivity for N. gaditana in chemostat cultures at four levels of nitrogen limitation were found to be 3.4 and 2.2 × 10−3 kg/m2·d for carbohydrates and TAG, respectively, at 56%NO3 limitation. The cell disruption rate of N. gaditana decreased along with nitrogen limitation, from 75% (at 200%NO3) to 17% (at 13%NO3). In the context of potentially recoverable energy for biofuels, P. kessleri showed good potential for biodiesel and high potential for bioethanol; by contrast, N. gaditana was found to be more efficient for biodiesel production only.
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