The aim of this study was to document the biodiversity of cyanobacteria genera isolated from intertidal and subtidal zones in Cabo Verde. The identification of the strains was conducted using a polyphasic study, comprising 16S rRNA gene maximum likelihood and Bayesian inference phylogeny, 16S rRNA identity (p-distance), 16S–23S ITS secondary structure, morphological, and habitat analyses. A total of 51 strains were isolated by micromanipulation and by streaking biomass onto Petri dishes with a solid medium. Seventeen strains were identified as belonging to the Salileptolyngbya genus and five to Leptothoe; sixteen strains were distributed across twelve genera. Thirteen strains were grouped into eight distinct clades, but could not be assigned to any cyanobacterial genus, indicating that they could be described as new cyanobacterial genera in the future. The phylogenies also exhibited isolates LEGE 181157, LEGE 181224, and LEGE 181227 clustered with Gibliniella, but in a separate clade from the G. alaskensis type. The 16S rRNA gene identity values among these new isolates and G. alaskensis ranged from 94.4% to 95.5%. The 16S–23S ITS dissimilarity between LEGE 181224 and G. alaskensis was 9.4%. Morphologically, these three LEGE strains differ from G. alaskensis in that they have trichomes that are never coiled and have diffluent mucilaginous envelopes, whereas G. alaskensis has coiled trichomes with firm sheaths. Based on these strains, we describe here a new species of Gibliniella.

Lichens are organisms constituted by a symbiotic relationship between a fungus (mycobiont) and a photoautotrophic partner (photobiont). Lichens produce several bioactive compounds; however, the biotechnological exploitation of this organism is hampered by its slow growth. To start studying the possibility of exploiting lichens as alternative sources of bioactive compounds, eighteen lichens were collected in the north of Portugal in order to isolate and study the bioactivity of their photobionts. It was possible to isolate and cultivate only eight photobionts. Three of them, LFR1, LFA2 and LCF3, belong to the Coelastrella genus, the other two (LFA1 and LCF1) belong to the Chlorella genus and for the remaining three photobionts, LFS1, LCA1 and LCR1, it was impossible to isolate their microalgae. These only grow in consortium with bacteria and/or cyanobacteria. All extracts showed antioxidant activity, mainly at a concentration of 10 mg.mL⁻¹. LFS1, a consortium extract, showed the highest antioxidant power, as well as the highest concentration of phenolic compounds (5.16 ± 0.53 mg of gallic acid equivalents (GAE).g⁻¹). The extracts under study did not show significant antibacterial activity against Escherichia coli, Listeria or Salmonella. The Coelastrella sp. and LFA1 extracts showed the highest hyaluronidase inhibition. The LFR1 extract at a concentration of 5 mg.mL⁻¹ showed the highest anti-inflammatory activity (79.77 ± 7.66%). The extracts of Coelastrella sp. and LFA1 also showed greater antidiabetic activity, demonstrating the high inhibitory power of α-amylase and α-glucosidase. LFR1 at a concentration of 5 mg.mL⁻¹, due to its selective cytotoxicity inhibiting the growth of cancer cells (Caco-2 cells), is a promising anticancer agent.

Cyanobacteria biodiversity remains underexplored despite their ecological importance and potential applications. To address this, we investigated two Leptolyngbya-like strains, LEGE 07170 and LEGE 191244, collected from marine tide pools in Portugal and Morocco using polyphasic approach. Phylogenetic analyses indicates that the strains form a distinct clade with strong statistical support in the Oculatellales order. The 16S rRNA gene identity matrix shows that the maximum shared values with the phylogenetically closest genera Gansulinema, Kaiparowitsia, Shahulinema, Aerofilum and Thermoleptolyngbya is consistently below 94.5%. Morphologically, LEGE 07170 and LEGE 191244 are indistinguishable to each other. Both optical and TEM analyses showed vacuole-like structures at the cells cross-walls and this character morphologically distinguishes these strains from their phylogenetically related genera. The 16S–23S ITS secondary structures also differed the LEGE-CC strains from their closest related genera.

Cyanobacteria are microorganisms that have remarkable adaptability and can inhabit various types of aquatic and terrestrial ecosystems worldwide, including extreme environments. This group of organisms is considered a rich source of secondary metabolites with potential biotechnological applications and has the capability to produce some potent cyanotoxins that can induce consequences to human health. The Blue Biotechnology and Ecotoxicology Culture Collection (LEGE-CC) is a biological resource center located at the Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), comprising more than 1200 different cyanobacterial and microalgae strains. Until now, 36 strains have been reported as producers of cyanotoxins distributed within different cyanobacterial orders. Recently, LEGE-CC has increased in numbers due to the isolation effort that has been made. In this work, a screening of more than 200 cyanobacterial isolates from subaerial and freshwater environments targeted the genes involved in the biosynthesis of cyanotoxins. As expected, genes involved in cylindrospermopsin, saxitoxin, anatoxin and microcystin production were detected by molecular biology tools. The strains where the genes were detected were grown and sent to liquid chromatography–mass spectrometry (LC-MS) to confirm the production of cyanotoxins. As a culture collection, the screening of cyanotoxins is an essential aspect of cyanobacterial research and provides a comprehensive idea of the production of these toxins for future works.

Cyanobacteria are considered a rich source of secondary metabolites with potential biotechnological applications. Additionally, they have the capability to produce some potent toxins (cyanotoxins) that can have consequences for both environmental and human health. This group of microorganisms with a long evolutionary history and a remarkable adaptability can be found both in aquatic and terrestrial ecosystems, including extreme environments (e.g., freshwater, marine, terrestrial, hot springs, deserts, etc.). Cyanotoxins can be classified into five functional groups according to their primary target organ or effects being designated as hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins. In this work, the presence of genes involved in the biosynthesis of cyanotoxins (microcystin, saxitoxin, cylindrospermopsin, and anatoxin) were screened from more than 200 strains of cyanobacteria. The isolates were obtained from different samples along the Moroccan Atlantic coast (several sampling sites from El Jadida to Essaouira), and from an ancient Portuguese cistern located at El Jadida. There is a gap in the literature regarding the presence of cyanotoxins in this region and some of the isolated strains are related to genera (e.g., Phormidium sp., Pseudanabaena sp., Leptolyngbya sp., Lyngbya sp., and Geitlerinema sp.) that have been reported as potential cyanotoxins producers. Future work will include detection by liquid chromatography–mass spectrometry (LC-MS) to confirm the production of cyanotoxins. Furthermore, the isolates will be deposited in our in-house culture collection (LEGE-CC), and will be available for future studies, increasing the size and diversity of the collection.