Natural magnetite ore as a harvesting agent for saline microalgae Microchloropsis salina

Schobesberger, Michael; Real, Bruna Kopp; Meijer, Dominique; Berensmeier, Sonja; Fraga-García, Paula

doi:10.1016/j.biteb.2021.100798

Cited by 3 publications

(8 citation statements)

References 53 publications

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“…netochemistry 2023, 9, x FOR PEER REVIEW 7 of forces because of the opposite net surface charge between magnetite and the algal cells, can be deduced from the Zeta potential values (Figure 4). This observation is in go accordance with previous reports, which found high adsorption values in the acidic ran [7,51], and in contrast to the behavior of larger particles, where we saw no harvesti enhancement at acidic pHs [37]. Generally, we do not observe large differences in the harvesting efficiency for t different particles, but this is not very surprising because the size differences are a minor (they are all in the same dimension range).…”

Section: Planetary Ball Millsupporting

confidence: 93%

“…Especially at acidic pH values, the interaction was much higher, caused by th available surface and also due to the advantageous situation for attractive elec Especially at acidic pH values, the interaction was much higher, caused by the higher available surface and also due to the advantageous situation for attractive electrostatic forces because of the opposite net surface charge between magnetite and the algal cells, as can be deduced from the Zeta potential values (Figure 4). This observation is in good accordance with previous reports, which found high adsorption values in the acidic range [7,51], and in contrast to the behavior of larger particles, where we saw no harvesting enhancement at acidic pHs [37]. netochemistry 2023, 9, x FOR PEER REVIEW 7 of forces because of the opposite net surface charge between magnetite and the algal cells, can be deduced from the Zeta potential values (Figure 4).…”

Section: Planetary Ball Millsupporting

confidence: 93%

“…Synthetically produced magnetic nanoparticles usually show saturation magnetization values in a broad range between 30 and 89 A m 2 kg −1 [22,[28][29][30][31][32][33][34][35][36]. The natural magnetite ore microparticles have higher saturation magnetization (91 A m 2 kg −1 ) and behave remanently [37]; their magnetization values correspond to the values reported in specialized literature for the magnetism of magnetite in soils [38,39].…”

Section: Introductionsupporting

confidence: 77%

“…All experiments were performed as technical duplicates. Additional information on the harvesting experimental setup can be found in previously presented research [37].…”

Section: Harvesting Experimentsmentioning

confidence: 99%

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From Micro to Nano: Grinding Natural Magnetite Ore for Microalgae Harvesting

Schobesberger,

Helmhagen,

Mende

et al. 2023

Magnetochemistry

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Microalgae represent a promising feedstock for sustainable biomass and energy. The low cell concentration after cultivation, however, limits the current application fields. Magnetic microalgae harvesting is a recent approach to overcome the economic limitations of exploiting this natural resource. Accordingly, different particle types have been applied, mainly synthetically produced magnetic nanoparticles, though none on an industrial scale. Particle sizes between a few micrometers and a few nanometers have not been tested. We expected 200–500 nm to be advantageous for harvesting and as a compromise between the highly available surface and good separation properties. However, this intermediate magnetite particle size between the micro- and nano-scale cannot be reached via chemical synthesis. Therefore, we ground natural magnetite ore in a planetary ball mill and an agitator bead mill producing particles in the targeted size range. Applying ore particles ground from ~6 µm to 250 nm yields harvesting efficiencies comparable to synthetically produced nanoparticles (Ø ~ 10 nm), with only half the BET surface. Complete harvesting of saline microalgae Microchloropsis salina is possible with ground particles at alkaline pH. We demonstrate the feasibility of a harvesting process with natural, low-cost, easily separable, and readily available magnetite ore particles as a promising step towards exploiting valuable microalgal products in life sciences.

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Section: Planetary Ball Millsupporting

confidence: 93%

Section: Planetary Ball Millsupporting

confidence: 93%

Section: Introductionsupporting

confidence: 77%

“…All experiments were performed as technical duplicates. Additional information on the harvesting experimental setup can be found in previously presented research [37].…”

Section: Harvesting Experimentsmentioning

confidence: 99%

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From Micro to Nano: Grinding Natural Magnetite Ore for Microalgae Harvesting

Schobesberger,

Helmhagen,

Mende

et al. 2023

Magnetochemistry

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“…This repulsion also occurs at pH 8.0 but not at 10.0. At this latter pH, we presume that the multivalent ions from the media increase the protein adsorption as previously observed [37] due to crystal nucleation of these multivalent ions, calcium, and magnesium, that form positively charged precipitates that accumulate on the BIONs' surface and increase the binding capacities of proteins due to electrostatic attractions. The effect of pH is stronger for protein adsorption without the presence of salts (Figure S2, Supporting Information), probably because then the water ions only interact with the proteins, and no competing proton association or dissociation reactions of salt ions take place.…”

Section: Protein Coronasupporting

confidence: 72%

Biocorona on Iron Oxide Nanoparticles in a Complex Biotechnological Environment: Analysis of Proteins, Lipids, and Carbohydrates

Abarca-Cabrera,

Milinovic,

Heitler

et al. 2023

Small Science

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Upon their introduction into a biological environment, nanoparticles are spontaneously covered by a variety of biomolecules, forming a (multi)layer called the “biocorona”. However, the interaction of small and large molecules with nanosized materials is not fully understood and in complex aqueous systems, even less, limiting their exploitation. The objective is to gain insights into the mass partitioning between the solid and the liquid phases for the most abundant groups of biological molecules in a biotechnological milieu. Herein, the biocorona composition is analyzed after the exposure of bare iron oxide nanoparticles to Microchloropsis salina lysates to evaluate the influence of the environment's pH, temperature, and ionic strength on the adsorption of proteins, lipids, and carbohydrates. Maximum adsorption capacities reach at pH 4.0 and yield 0.47, 0.08, and 0.11 g g−1 for proteins, fatty acids, and carbohydrates, respectively. The increase in ionic strength and temperature of the environment promotes protein adsorption, the decrease in temperature raises fatty acid adsorption, and acidic pHs foster the adsorption of the three types of biomolecules. Abundance of the biomolecules plays a key role in the biocorona content. This approach should lead to further studies on complex systems to modulate the adsorption at the bio–nano interface.

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Recent advancements of coagulation–flocculation in microalgal downstream processes

Ummalyma

2025

Algal Bioreactors

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Natural magnetite ore as a harvesting agent for saline microalgae Microchloropsis salina

Cited by 3 publications

References 53 publications

From Micro to Nano: Grinding Natural Magnetite Ore for Microalgae Harvesting

From Micro to Nano: Grinding Natural Magnetite Ore for Microalgae Harvesting

Biocorona on Iron Oxide Nanoparticles in a Complex Biotechnological Environment: Analysis of Proteins, Lipids, and Carbohydrates

Recent advancements of coagulation–flocculation in microalgal downstream processes

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