Role of zinc as an essential microelement for algal growth and concerns about its potential environmental risks

El-Agawany, Nagwa; Kaamoush, Mona

doi:10.1007/s11356-022-20536-z

Cited by 12 publications

(5 citation statements)

References 31 publications

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“…At low concentrations, ZnO NPs can act as a source of zinc. Zinc plays a significant role in chlorophyll formation, which is essential for photosynthesis [39]. Therefore, the presence of ZnO NPs can enhance microalgae growth and improve nutrient uptake, especially under sub-optimal nitrate concentrations (0, 150, and 300 mg/L), as seen in Figure 1.…”

Section: Effect Of Zno Nps On Nutrient Uptakementioning

confidence: 99%

Short-Term Toxicity of ZnO Nanoparticles on Microalgae at Different Initial Nutrient Concentrations

2023

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The aim of this work was to investigate the combined short-term toxic effect of zinc oxide (ZnO) nanoparticles (NPs) and nitrate concentration of the medium on freshwater microalgae. For this purpose, freshwater microalgae Chlorococcum sp. was cultivated in modified Blue-Green medium (BG-11) containing nitrate concentrations ranging from 0 to 300 mg/L, and exposed to ZnO NPs in different concentrations (0.081 to 810 mg/L) for a period up to 96 h. The experimental results revealed that algal growth was affected by the exposure time, NPs concentrations, and mainly the initial nitrate concentration. Differences in microalgae growth rates were observed. The toxic effect of ZnO NPs was higher on microalgae cultured in modified BG-11 with low and high nitrate concentrations. During the 4-day exposure, the highest growth rates were observed at 24 h at an initial nitrate concentration of 50 mg/L; 1.94 d−1 and 0.22 d−1 for 0 and 810 mg/L ZnO NPs, respectively. Nitrate uptake by algal biomass reached up to 40.1% after 96 h of operation in the control culture with an initial nitrate concentration of 50 mg/L. Finally, the results of this study showed the need for the investigation of ZnO NPs toxicity on microalgae under optimum and stressful nutrient conditions for microalgae growth.

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Section: Effect Of Zno Nps On Nutrient Uptakementioning

confidence: 99%

Short-Term Toxicity of ZnO Nanoparticles on Microalgae at Different Initial Nutrient Concentrations

2023

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“…4 b and c, of two different sections of the branch confirm the presence of U with an increasing amount in the superficial tissues. The competition between U and other cations has not been considered here, but it is worth bearing in mind that experiments have been conducted in natural seawater, where essential metal cations (Ca 2+ , Mg 2+ or Zn 2+ ) play an important role in the biomass survival 53 – 55 . Therefore, accumulation of U on the algal surface may interfere with the uptake of such essential cations, as they probably share the same channels of absorption but this is beyond the scope of the present study at this time.…”

Section: Resultsmentioning

confidence: 99%

Exploring uranium bioaccumulation in the brown alga Ascophyllum nodosum: insights from multi-scale spectroscopy and imaging

Zerbini,

Solari,

Orange

et al. 2024

Sci Rep

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Legacy radioactive waste can be defined as the radioactive waste produced during the infancy of the civil nuclear industry’s development in the mid-20th Century, a time when, unfortunately, waste storage and treatment were not well planned. The marine environment is one of the environmental compartments worth studying in this regard because of legacy waste in specific locations of the seabed. Comprising nearly 70% of the earth’s service, the oceans are the largest and indeed the final destination for contaminated fresh waters. For this reason, long-term studies of the accumulation biochemical mechanisms of metallic radionuclides in the marine ecosystem are required. In this context the brown algal compartment may be ecologically relevant because of forming large and dense algal beds in coastal areas and potential important biomass for contamination. This report presents the first step in the investigation of uranium (U, an element used in the nuclear cycle) bioaccumulation in the brown alga Ascophyllum nodosum using a multi-scale spectroscopic and imaging approach. Contamination of A. nodosum specimens in closed aquaria at 13 °C was performed with a defined quantity of U(VI) (10–5 M). The living algal uptake was quantified by ICP-MS and a localization study in the various algal compartments was carried out by combining electronic microscopy imaging (SEM), X-ray Absorption spectroscopy (XAS) and micro X-ray Florescence (μ-XRF). Data indicate that the brown alga is able to concentrate U(VI) by an active bioaccumulation mechanism, reaching an equilibrium state after 200 h of daily contamination. A comparison between living organisms and dry biomass confirms a stress-response process in the former, with an average bioaccumulation factor (BAF) of 10 ± 2 for living specimens (90% lower compared to dry biomass, 142 ± 5). Also, these results open new perspectives for a potential use of A. nodosum dry biomass as uranium biosorbent. The different partial BAFs (bioaccumulation factors) range from 3 (for thallus) to 49 (for receptacles) leading to a compartmentalization of uranium within the seaweed. This reveals a higher accumulation capacity in the receptacles, the algal reproductive parts. SEM images highlight the different tissue distributions among the compartments with a superficial absorption in the thallus and lateral branches and several hotspots in the oospheres of the female individuals. A preliminary speciation XAS analysis identified a distinct U speciation in the gametes-containing receptacles as a pseudo-autunite phosphate phase. Similarly, XAS measurements on the lateral branches (XANES) were not conclusive with regards to the occurrence of an alginate-U complex in these tissues. Nonetheless, the hypothesis that alginate may play a role in the speciation of U in the algal thallus tissues is still under consideration.

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“…It is added to US-EPA and OECD media in concentrations of 0.07 and 0.06 nmol L −1 , respectively (OECD 2011 ; US-EPA 2012 ). Zn makes part of many enzymes and is required for photosynthesis and energy storage (El-Agawany and Kaamoush 2023 ). This micronutrient is present in US-EPA and OECD media at concentrations of 24 and 22 nmol L −1 , respectively (OECD 2011 ; US-EPA 2012 ).…”

Section: Alga Nutritionmentioning

confidence: 99%

Features of the microalga Raphidocelis subcapitata: physiology and applications

Machado,

Soares

2024

Appl Microbiol Biotechnol

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The microalga Raphidocelis subcapitata was isolated from the Nitelva River (Norway) and subsequently deposited in the collection of the Norwegian Institute of Water Research as “Selenastrum capricornutum Printz”. This freshwater microalga, also known as Pseudokirchneriella subcapitata, acquired much of its notoriety due to its high sensitivity to different chemical species, which makes it recommended by different international organizations for the assessment of ecotoxicity. However, outside this scope, R. subcapitata continues to be little explored. This review aims to shed light on a microalga that, despite its popularity, continues to be an “illustrious” unknown in many ways. Therefore, R. subcapitata taxonomy, phylogeny, shape, size/biovolume, cell ultra-structure, and reproduction are reviewed. The nutritional and cultural conditions, chronological aging, and maintenance and preservation of the alga are summarized and critically discussed. Applications of R. subcapitata, such as its use in aquatic toxicology (ecotoxicity assessment and elucidation of adverse toxic outcome pathways) are presented. Furthermore, the latest advances in the use of this alga in biotechnology, namely in the bioremediation of effluents and the production of value-added biomolecules and biofuels, are highlighted. To end, a perspective regarding the future exploitation of R. subcapitata potentialities, in a modern concept of biorefinery, is outlined. Graphical Abstract Key points • An overview of alga phylogeny and physiology is critically reviewed. • Advances in alga nutrition, cultural conditions, and chronological aging are presented. • Its use in aquatic toxicology and biotechnology is highlighted.

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Role of zinc as an essential microelement for algal growth and concerns about its potential environmental risks

Cited by 12 publications

References 31 publications

Short-Term Toxicity of ZnO Nanoparticles on Microalgae at Different Initial Nutrient Concentrations

Short-Term Toxicity of ZnO Nanoparticles on Microalgae at Different Initial Nutrient Concentrations

Exploring uranium bioaccumulation in the brown alga Ascophyllum nodosum: insights from multi-scale spectroscopy and imaging

Features of the microalga Raphidocelis subcapitata: physiology and applications

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