Effect of biodegradable chelating ligands on Fe uptake in and growth of marine microalgae

AbstractIron (Fe) is an essential nutrient for microalgal metabolism. The low solubility of Fe in oxic aquatic environments can be a growth-limiting factor for phytoplankton. Synthetic chelating agents, such as ethylenediaminetetraacetic acid (EDTA), are used widely to maintain Fe in solution for microalgal cultivation. The non-biodegradable nature of EDTA, combined with sub-optimal bioavailability of Fe-EDTA complexes to microalgae, indicates opportunity to improve microalgal cultivation practices that amplify production efficiency and environmental compatibility. In the present study, the effects of four organic chelating ligands known to form readily bioavailable organic complexes with Fe in natural aquatic environments were investigated in relation to growth and biochemical composition of two marine microalgae grown as live feeds in shellfish hatcheries (Chaetoceros calcitrans and Tisochrysis lutea). Three saccharides, alginic acid (ALG), glucuronic acid (GLU), and dextran (DEX), as well as the siderophore desferrioxamine B (DFB), were compared to EDTA. Organic ligands characterized by weaker binding capacity for cationic metals (i.e., ALG, GLU, DEX) significantly improved microalgal growth and yields in laboratory-scale static batch cultures or bubbled photobioreactors. Maximal microalgal growth enhancement relative to the control (e.g., EDTA) was recorded for GLU, followed by ALG, with 20–35% increase in specific growth rate in the early stages of culture development of C. calcitrans and T. lutea. Substitution of EDTA with GLU resulted in a 27% increase in cellular omega 3-polyunsaturetd fatty acid content of C. calcitrans and doubled final cell yields. Enhanced microalgal culture performance is likely associated with increased intracellular Fe uptake efficiency combined with heterotrophic growth stimulated by the organic ligands. Based upon these results, we propose that replacement of EDTA with one of these organic metal-chelating ligands is an effective and easily implementable strategy to enhance the environmental compatibility of microalgal cultivation practices while also maximizing algal growth and enhancing the nutritional quality of marine microalgal species commonly cultured for live-feed applications in aquaculture.

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Ethylene Polymerization by Monochloro Non-Bridged Half-Metallocene-type Zirconium Complexes Containing Phosphine Oxide-(thio)phenolate Chelating Ligands as Catalyst at High Temperature

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1095.2013.30198 ◽

2013 ◽

Vol 30 (11) ◽

pp. 1293

Author(s):

Sanrong LIU ◽

Jingyu LIU ◽

Yuesheng LI

Keyword(s):

High Temperature ◽

Phosphine Oxide ◽

Ethylene Polymerization ◽

Chelating Ligands ◽

Zirconium Complexes

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A photobioreactor using Nannochloropsis oculata marine microalgae for removal of polycyclic aromatic hydrocarbons and sorption of metals in produced water

Chemosphere ◽

10.1016/j.chemosphere.2021.130775 ◽

2021 ◽

pp. 130775

Author(s):

Isadora Machado Marques ◽

Adna Caroline Vale Oliveira ◽

Olivia Maria Cordeiro de Oliveira ◽

Emerson Andrade Sales ◽

Ícaro Thiago Andrade Moreira

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Aromatic Hydrocarbons ◽

Produced Water ◽

Nannochloropsis Oculata ◽

Marine Microalgae ◽

Polycyclic Aromatic

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Removal of Pharmaceutical Micropollutants with Integrated Biochar and Marine Microalgae

Microorganisms ◽

10.3390/microorganisms9010004 ◽

2020 ◽

Vol 9 (1) ◽

pp. 4

Author(s):

Amin Mojiri ◽

Maedeh Baharlooeian ◽

Reza Andasht Kazeroon ◽

Hossein Farraji ◽

Ziyang Lou

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Response Surface Methodology ◽

Cell Viability ◽

Response Surface ◽

Contact Time ◽

Marine Microalgae ◽

Chaetoceros Muelleri ◽

Mean Squared Errors ◽

High Concentrations

Using microalgae to remove pharmaceuticals and personal care products (PPCPs) micropollutants (MPs) have attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in remediating PPCPs. Three persistent PPCPs, namely, carbamazepine (CBZ), sulfamethazine (SMT) and tramadol (TRA), were treated with a combination of Chaetoceros muelleri and biochar in a photobioreactor during this study. Two reactors were run. The first reactor comprised Chaetoceros muelleri, as the control, and the second reactor comprised Chaetoceros muelleri and biochar. The second reactor showed a better performance in removing PPCPs. Through the response surface methodology, 68.9% (0.330 mg L−1) of CBZ, 64.8% (0.311 mg L−1) of SMT and 69.3% (0.332 mg L−1) of TRA were removed at the initial concentrations of MPs (0.48 mg L−1) and contact time of 8.1 days. An artificial neural network was used in optimising elimination efficiency for each MP. The rational mean squared errors and high R2 values showed that the removal of PPCPs was optimised. Moreover, the effects of PPCPs concentration (0–100 mg L−1) on Chaetoceros muelleri were studied. Low PPCP concentrations (<40 mg L−1) increased the amounts of chlorophyll and proteins in the microalgae. However, cell viability, chlorophyll and protein contents dramatically decreased with increasing PPCPs concentrations (>40 mg L−1).

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