Advances in Microalgae Toxins: Production, Detection, and Application

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: closed (2 September 2023) | Viewed by 11287

Special Issue Editor


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Guest Editor
Department of Chemical Engineering, Universidad de Almería, 04120 Almería, Spain
Interests: biochemical engineering; bioprocess; technology; microalgae; marine toxins; marine ecology; cell lysis; chemical engineering; industrial biotechnology; photobioreactors
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Special Issue Information

Dear Colleagues,

Dinoflagellate microalgae are an important source of marine metabolites. These toxins and bioactives are of increasing interest because of their influence on the safety of seafood and their potential medical and biotechnological applications. Nowadays, bioactive supply is still the main bottleneck due to the difficulty of growing dinoflagellates in photobioreactors. Only sparing quantities of dinoflagellate bioactives are available for researchers, hindering their characterization and evaluation for possible applications. Despite this, in recent years advances have been made in every aspect related to the biotechnological exploitation of this resource. For instance, novel molecules and potential applications for dinoflagellate bioactives have been shown. Additionally, new approaches for culturing and downprocessing biomasses have been presented.

This Special Issue aims to provide insight into the potential of dinoflagellate’s bioactives to develop bioprocess with these microalgae and the obstacles that remain. Accordingly, it will foster contributions focused on dinoflagellates that address biodiscovery, metabolite characterization, cell culture, and bioprocess optimization (upstream and downstream). This Special Issue is intended to be of interest for those involved in the field from different perspectives.

Dr. Juan Jose Gallardo Rodriguez
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • dinoflagellate
  • bioactives
  • bioprocess
  • marine toxins

Published Papers (5 papers)

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Research

13 pages, 2198 KiB  
Article
The Influence of the Toxic Dinoflagellate Alexandrium minutum, Grown under Different N:P Ratios, on the Marine Copepod Acartia tonsa
by Epaminondas D. Christou, Ioanna Varkitzi, Isabel Maneiro, Soultana Zervoudaki and Kalliopi Pagou
Toxins 2023, 15(4), 287; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins15040287 - 16 Apr 2023
Viewed by 1865
Abstract
HABs pose a threat to coastal ecosystems, the economic sector and human health, and are expanding globally. However, their influence on copepods, a major connector between primary producers and upper trophic levels, remains essentially unknown. Microalgal toxins can eventually control copepod survival and [...] Read more.
HABs pose a threat to coastal ecosystems, the economic sector and human health, and are expanding globally. However, their influence on copepods, a major connector between primary producers and upper trophic levels, remains essentially unknown. Microalgal toxins can eventually control copepod survival and reproduction by deterring grazing and hence reducing food availability. We present several 24-h experiments in which the globally distributed marine copepod, Acartia tonsa, was exposed to different concentrations of the toxic dinoflagellate, Alexandrium minutum, grown under three N:P ratios (4:1, 16:1 and 80:1), with the simultaneous presence of non-toxic food (the dinoflagellate Prorocentrum micans). The different N:P ratios did not affect the toxicity of A. minutum, probably due to the low toxicity of the tested strain. Production of eggs and pellets as well as ingested carbon appeared to be affected by food toxicity. Toxicity levels in A. minutum also had an effect on hatching success and on the toxin excreted in pellets. Overall, A. minutum toxicity affected the reproduction, toxin excretion and, to an extent, the feeding behavior of A. tonsa. This work indicates that even short-term exposure to toxic A. minutum can impact the vital functions of A. tonsa and might ultimately pose serious threats to copepod recruitment and survival. Still, further investigation is required for identifying and understanding, in particular, the long-term effects of harmful microalgae on marine copepods. Full article
(This article belongs to the Special Issue Advances in Microalgae Toxins: Production, Detection, and Application)
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18 pages, 3632 KiB  
Article
Effect of Nitrogen, Phosphorous, and Light Colimitation on Amphidinol Production and Growth in the Marine Dinoflagellate Microalga Amphidinium carterae
by Alejandro Molina-Miras, Alejandro Bueso-Sánchez, María del Carmen Cerón-García, Asterio Sánchez-Mirón, Antonio Contreras-Gómez and Francisco García-Camacho
Toxins 2022, 14(9), 594; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14090594 - 28 Aug 2022
Cited by 3 | Viewed by 1918
Abstract
The marine dinoflagellate microalga Amphidinium carterae is a source of amphidinols, a fascinating group of polyketide metabolites potentially useful in drug design. However, Amphidinium carterae grows slowly and produces these toxins in tiny amounts, representing a hurdle for large-scale production. Understanding dinoflagellate growth [...] Read more.
The marine dinoflagellate microalga Amphidinium carterae is a source of amphidinols, a fascinating group of polyketide metabolites potentially useful in drug design. However, Amphidinium carterae grows slowly and produces these toxins in tiny amounts, representing a hurdle for large-scale production. Understanding dinoflagellate growth kinetics under different photobioreactor conditions is imperative for promoting the successful implementation of a full-scale integrated bioproduct production system. This study evaluates the feasibility of growing Amphidinium carterae under different ranges of nitrogen concentration (NO3 = 882–2646 µM), phosphorus concentration (PO33− = 181–529 µM), and light intensity (Y0 = 286–573 µE m−2 s−1) to produce amphidinols. A mathematical colimitation kinetic model based on the “cell quota” concept is developed to predict both algal growth and nutrient drawdown, assuming that all three variables (nitrogen, phosphorous and light) can simultaneously colimit microalgal growth. The model was applied to the semicontinuous culture of the marine microalgae Amphidinium carterae in an indoor LED-lit raceway photobioreactor. The results show that both growth and amphidinol production strongly depend on nutrient concentrations and light intensity. Nonetheless, it was possible to increase Amphidinium carterae growth while simultaneously promoting the overproduction of amphidinols. The proposed model adequately describes Amphidinium carterae growth, nitrate and phosphate concentrations, and intracellular nitrogen and phosphorus storage, and has therefore the potential to be extended to other systems used in dinoflagellate cultivation and the production of bioproducts obtained therein. Full article
(This article belongs to the Special Issue Advances in Microalgae Toxins: Production, Detection, and Application)
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19 pages, 3750 KiB  
Article
The Isolation of Specialty Compounds from Amphidinium carterae Biomass by Two-Step Solid-Phase and Liquid-Liquid Extraction
by Mercedes López-Rodríguez, Lorenzo López-Rosales, Giulia Diletta Necci, María del Carmen Cerón-García, Elvira Navarro-López, Juan José Gallardo-Rodríguez, Ana Isabel Tristán, Ana Cristina Abreu and Francisco García-Camacho
Toxins 2022, 14(9), 593; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14090593 - 28 Aug 2022
Cited by 1 | Viewed by 2045
Abstract
The two main methods for partitioning crude methanolic extract from Amphidinium carterae biomass were compared. The objective was to obtain three enriched fractions containing amphidinols (APDs), carotenoids, and fatty acids. Since the most valuable bioproducts are APDs, their recovery was the principal goal. [...] Read more.
The two main methods for partitioning crude methanolic extract from Amphidinium carterae biomass were compared. The objective was to obtain three enriched fractions containing amphidinols (APDs), carotenoids, and fatty acids. Since the most valuable bioproducts are APDs, their recovery was the principal goal. The first method consisted of a solid-phase extraction (SPE) in reverse phase that, for the first time, was optimized to fractionate organic methanolic extracts from Amphidinium carterae biomass using reverse-phase C18 as the adsorbent. The second method consisted of a two-step liquid-liquid extraction coupled with SPE and, alternatively, with solvent partitioning. The SPE method allowed the recovery of the biologically-active fraction (containing the APDs) by eluting with methanol (MeOH): water (H2O) (80:20 v/v). Alternatively, an APD purification strategy using solvent partitioning proved to be a better approach for providing APDs in a clear-cut way. When using n-butanol, APDs were obtained at a 70% concentration (w/w), whereas for the SPE method, the most concentrated fraction was only 18% (w/w). For the other fractions (carotenoids and fatty acids), a two-step liquid-liquid extraction (LLE) method coupled with the solvent partitioning method presented the best results. Full article
(This article belongs to the Special Issue Advances in Microalgae Toxins: Production, Detection, and Application)
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18 pages, 5611 KiB  
Article
Physiological Response of Atlantic Salmon (Salmo salar) to Long-Term Exposure to an Anesthetic Obtained from Heterosigma akashiwo
by Ana Teresa Gonçalves, Alejandra Llanos-Rivera, Miguel Ruano, Veronica Avello, Juan José Gallardo-Rodriguez and Allisson Astuya-Villalón
Toxins 2022, 14(8), 575; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14080575 - 22 Aug 2022
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Abstract
Despite the invaluable role of anesthetics as a tool for ensuring animal welfare in stressful situations, there is currently a lack of anesthetic drugs that meet the requirements of intensive aquaculture. In response to the growing interest in anesthetic substances of natural origin, [...] Read more.
Despite the invaluable role of anesthetics as a tool for ensuring animal welfare in stressful situations, there is currently a lack of anesthetic drugs that meet the requirements of intensive aquaculture. In response to the growing interest in anesthetic substances of natural origin, this study evaluated the physiological and health impact of an anesthetic based on an extract of the microalga Heterosigma akashiwo on juvenile salmon (Salmo salar) exposed for a period of 72 h. To simulate a condition closer to reality where fish are subjected to stimuli (e.g., transport), the animals were exposed to 50 mg L−1 of algal extract and to physical stress. Functional, physiological, and histological parameters were evaluated in blood and tissues at different sampling periods (0, 24, and 72 h). There was no mortality and the induction and recovery times observed were within the established criteria for anesthetic efficacy. The anesthetic extract did not induce any side effects, such as stress or metabolic damage, indicating that this extract is a viable option for supporting fish welfare during deleterious events. This study provides information to support that the anesthetic extract tested, derived from H. akashiwo, is a promising candidate drug for operations requiring sedation (e.g., Salmonid transport). Full article
(This article belongs to the Special Issue Advances in Microalgae Toxins: Production, Detection, and Application)
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11 pages, 3567 KiB  
Article
Genomic Analysis of Sphingopyxis sp. USTB-05 for Biodegrading Cyanobacterial Hepatotoxins
by Chao Liu, Qianqian Xu, Zhenzhen Zhao, Haiyang Zhang, Xiaolu Liu, Chunhua Yin, Yang Liu and Hai Yan
Toxins 2022, 14(5), 333; https://0-doi-org.brum.beds.ac.uk/10.3390/toxins14050333 - 9 May 2022
Cited by 8 | Viewed by 2091
Abstract
Sphingopyxis sp. USTB-05, which we previously identified and examined, is a well-known bacterial strain for biodegrading cyanobacterial hepatotoxins of both nodularins (NODs) and microcystins (MCs). Although the pathways for biodegrading the different types of [D-Asp1] NOD, MC-YR, MC-LR and MC-RR by [...] Read more.
Sphingopyxis sp. USTB-05, which we previously identified and examined, is a well-known bacterial strain for biodegrading cyanobacterial hepatotoxins of both nodularins (NODs) and microcystins (MCs). Although the pathways for biodegrading the different types of [D-Asp1] NOD, MC-YR, MC-LR and MC-RR by Sphingopyxis sp. USTB-05 were suggested, and several biodegradation genes were successfully cloned and expressed, the comprehensive genomic analysis of Sphingopyxis sp. USTB-05 was not reported. Here, based on second and third generation sequencing technology, we analyzed the whole genome of Sphingopyxis sp. USTB-05, which is 4,679,489 bp and contains 4,312 protein coding genes. There are 88 protein-coding genes related to the NODs and MCs biodegradation, of which 16 genes (bioA, hmgL, hypdh, speE, nspC, phy, spuC, murD, glsA, ansA, ocd, crnA, ald, gdhA, murC and murI) are unique. These genes for the transformation of phenylacetic acid CoA (PA-CoA) to CO2 were also found in Sphingopyxis sp. USTB-05. This study expands the understanding of the pathway for complete biodegradation of cyanobacterial hepatotoxins by Sphingopyxis sp. USTB-05. Full article
(This article belongs to the Special Issue Advances in Microalgae Toxins: Production, Detection, and Application)
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