A green microbe for a sustainable future: the versatile applications of Nostoc commune

Abstract

Nostoc commune, a terrestrial nitrogen-fixing cyanobacterium, presents a multifaceted opportunity for sustainable development through its ecological resilience, nutritional richness, and biotechnological versatility. This review synthesizes and critically evaluates current knowledge on N. commune, with an emphasis on its taxonomy, morpho-physiology, and ecological roles, particularly its contributions to nutrient cycling, stress tolerance, and symbiotic associations. Comparative insights into nitrogen-fixing efficiency, metabolite production, and strategies to mitigate cyanotoxin-related risks are discussed alongside emerging applications in functional foods, nutraceuticals, and sustainable agriculture. Its nutritional profile and adaptability position N. commune as a low-impact alternative within integrated food and health systems. Additionally, the review explores its significance in cultural traditions, biotechnology, and environmental remediation. Despite its promise, challenges remain, including variable metabolite profiles and safety concerns related to neurotoxins such as β-N-methylamino-L-alanine, necessitating targeted strain selection and regulatory frameworks. By integrating advances in genetic engineering, circular bioeconomy strategies, and community-centred approaches, N. commune could become a cornerstone of climate-smart agriculture, sustainable food systems, and global health solutions.

Sustainability Statement.

This study primarily advances SDG 2: Zero Hunger by highlighting Nostoc commune as a sustainable, nitrogen-fixing microbe that improves soil fertility and strengthens food security. By providing an eco-friendly alternative to synthetic fertilizers, it reduces environmental degradation and promotes climate-resilient agricultural practices that enhance long-term productivity. The organism’s capacity to restore degraded soils further reinforces its value for sustainable farming systems. In addition, N. commune offers bioactive compounds relevant to health and nutraceutical applications, while its role in promoting circular resource use and lowering greenhouse gas emissions also contributes to other SDGs. Additional contributions are relevant to;

SDG 3: Good Health and Well-being

SDG 12: Responsible Consumption and Production

SDG 13: Climate Action

Introduction

Investigating ecologically significant microbes is crucial in the emerging field of green microbiology. Nostoc commune, a cyanobacterium with considerable ecological, agricultural, and cultural significance (Nweze 2011, Garlapati et al. 2019), stands out as a model organism that deserves focus. With an emphasis on N. commune’s role in promoting sustainability as a suitable bioresource for agriculture, nutraceuticals, health, and environmental management, this review explores the multidimensional value and implications of studying it with a critical evaluation of recent advances and challenges. Nostoc commune belongs to a class of cyanobacteria known for their diverse abilities, including fixing nitrogen, producing oxygen through photosynthesis, and being resistant to harsh environmental conditions (Singh et al. 2016). Nostoc commune plays an ecologically essential role, yet its adaptability also plays a significant role in biotechnological applications, traditional cultural practices, and agricultural productivity (Dodds et al. 1995, Esch 2014, Christi 2023). Nostoc commune can be used in biotechnology to produce biofertilizers that enhance soil fertility and plant growth (Esch 2014), while in traditional cultural practices, it serves as food (Johnson 2008, Li and Guo 2018) and has medicinal uses such as treating skin infections or improving overall health (Tseng et al. 2021). Despite this historical use in traditional cuisines and herbal medicine, critical questions remain about the scalability, safety, and comparative advantages of N. commune relative to other cyanobacteria such as Spirulina (a well-established ‘cash crop’) and Anabaena relevant to the cyanobacterial industry (Churasia and Apte 2011, Alfadhly et al. 2022a, 2022b, Abreu et al. 2023, Jalili et al. 2024). Nostoc commune can also improve crop yields through its nitrogen-fixing capabilities by providing nitrogen directly to plants (Sand-Jensene 2014). Belton et al. (2021) illustrates the effect of N. commune on human health (Li and Guo 2018).

Fig. 1 shows how N. commune or its derived extracts demonstrate broad therapeutic potential through multiple regulatory mechanisms that benefit human health, as evidenced by both ex vivo and in vivo experimental studies discussed and derived from the literature in the study by Li et al. (2018). The primary protective effects are mediated through potent antioxidant activity, including the scavenging of reactive oxygen species such as superoxide anion, peroxyl, hydroxyl, and peroxynitrite radicals, while simultaneously enhancing endogenous antioxidant enzyme systems, including superoxide dismutase, catalase, and glutathione peroxidase. These compounds also exhibit significant immune system modulation properties through complement system activation and broader immune regulation mechanisms. The therapeutic benefits extend across multiple organ systems, with cardiovascular protection achieved through cholesterol management and lipid peroxidation reduction, hepatic protection against oxidative damage, pulmonary anti-inflammatory effects with reduced cellular migration, and gastrointestinal benefits, including anticancer properties in colon tissue through apoptosis induction and reduced cellular invasion. Additionally, N. commune extracts demonstrate haematological benefits with potential antileukaemic effects and cellular protection mechanisms. The convergence of evidence from laboratory and animal studies, as illustrated, supports the characterization of N. commune as a multifunctional therapeutic agent with antioxidative, anticarcinogenic, immune-regulating, and hypocholesterolemic properties that collectively contribute to its comprehensive health-promoting effects. An extensive breakdown of this impact in human-related diseases is provided in the study by Li and Guo (2018).

Figure 1.

Putative effect of N. commune and its extracts on human health (Li and Guo 2018). ABTS–2,2′-azino-bis (3-ethylbenzothiazoline-6-suphonic acid, SOD, Superoxide Dismutase; CAT, Catalase; GPX, Glutathione Peroxidase; NO, Nitric Oxide; EMT, Epithelial-Mesenchymal Transition program; Mϕ, Activated Monocyte

The functional diversity of N. commune, including its nitrogen-fixing ability, photosynthesis, and interaction with other organisms (Dodds et al. 1995, Jiang et al. 2020, Ladha et al. 2022), makes it important in green microbiology (Nazen-Bokaee et al. 2021) and provides opportunities for new insights into eco-friendly nitrogen management by offering a natural alternative to synthetic fertilizers. Its nitrogen-fixing ability reduces chemical runoff, greenhouse gas emissions, and soil degradation, making agriculture more sustainable. Understanding its metabolic pathways can help develop biofertilizers that enhance soil fertility while minimizing pollution. This contributes to a more circular and regenerative agricultural system. Its drought resistance and stress tolerance make it valuable for climate-resilient farming and land restoration. These attributes position it as a promising candidate for regenerative agriculture and low-input cropping systems.

Green Microbiology focuses on microbial processes to provide bioremediation, waste management, renewable energy production, and sustainable agriculture with tools and solutions that are environmentally friendly (Akinsemolu 2023). Advances in these fields, which are of utmost importance in the age of climate change and rising global demand for sustainable practices, may be made possible by better understanding the biological roles, mechanisms, and interactions of N. commune. Like other cyanobacteria, it has the potential to be a natural biofertilizer (Singh et al. 2016), and by understanding its nitrogen fixation abilities and interactions with plants, we can develop eco-friendly methods to improve crop yields. Nostoc commune captures atmospheric nitrogen through nitrogen fixation and converts it into a usable form, promoting plant growth and increasing green carbon stored in the ecosystem (Ramakrishnan et al. 2023). This can be a valuable tool in combating climate change. All these necessitate the significance of a thorough investigation into the N. commune, which will ultimately shed light on how this organism interacts with different ecological systems and may even be able to influence them to achieve more sustainable results.

Advances in omics, molecular genetics, and cultivation technologies have opened new avenues that could enhance the productivity of N. commune, mitigating safety concerns associated with cyanotoxins such as β-N-methylamino-L-alanine (BMAA), and expanding its biotechnological potential. For instance, sequencing the genomes of N. commune offers a blueprint to identify genes underlying desirable traits such as growth and bioactive compound production, as well as undesirable cyanotoxin synthesis, thereby enabling targeted genetic manipulation and informing strain selection and improvement through insights into their evolutionary history and genetic diversity as observed in the study by Lui et al. (2022) that applied microfluidics, single-cell sequencing, and de novo assembly to reduce contamination and recover a high-quality, complete genome of Nostoc strain CCCryo 231–06 (Liu et al. 2022). In the study by Koksharova et al. (2021), proteomic studies showed how Nostoc sp. PCC 7120 responds to BMAA, indicating specific protein downregulation related to nitrogen fixation and photosynthesis (Koksharove et al. 2021). The study by Mouga et al. (2024) explored various factors to optimize Nostoc sp. growth and productivity under controlled laboratory conditions, demonstrating the impact of nitrogen supplementation and light quality (Mouga et al. 2024). Optimizing nutrient media, biomass levels, light (intensity and wavelength), and temperature in controlled settings can greatly enhance productivity. The study by Boopathi and Ki (2014) shows that environmental factors like nutrient availability and stress can impact cyanotoxin synthesis (Boopathi and Ki 2014). The extracellular polymeric substances (EPS) of N. commune have metal-chelating properties, making them promising for bioremediation applications (Liang et al. 2022).

This review therefore consolidates current knowledge and recent advances on N. commune, emphasizing comparative assessments of its nitrogen-fixing efficiency, stress tolerance, and metabolite production; strategies to mitigate cyanotoxin-related health risks via strain selection, genetic engineering, and detoxification processes; emerging insights into its bioactive compounds for functional foods and pharmaceuticals; and the challenges and opportunities in deploying it as a climate-smart, circular bioresource. By critically assessing these aspects, this review contributes to a clearer understanding of N. commune’s unique value proposition and research priorities for its sustainable integration into agriculture, nutrition, human health, and environmental management.

Methodology

This review employed a narrative integrative approach to consolidate and critically appraise current knowledge and recent advances on N. commune. Literature was identified through structured searches of electronic databases, including Google Scholar and Google search, PubMed, Scopus, and Web of Science, complemented by manual screening of reference lists and grey literature.

Search terms combined controlled vocabulary and free-text keywords related to taxonomy, genomics, ecological roles, nitrogen fixation, food, bioactive compounds, and biotechnological applications of N. commune. No date restrictions were applied. No restriction of study type was done, and relevant studies were considered when they provided relevant primary data or comprehensive syntheses.

Articles were screened for relevance based on our study aim, and full texts were analysed. Data and relevant information were extracted and synthesized qualitatively to provide an integrated perspective on the organism’s taxonomy, ecological significance, nutritional profile, human and environmental health implications, functional applications, and future prospects. Given the scope and heterogeneity of the evidence base, no formal quality assessment or meta-analysis was conducted.

Taxonomy and characteristics

Nostoc is one of the five genera within the family Nostocaceae, with the name ‘Nostoc’ being used in Europe for around 500 years (Potts 1997). Known as ‘Dimuer’ in China, N. commune has been utilized as a dietary supplement and herbal medicine (Diao and Yang 2014). In Chinese medicine, it is been proposed that it has potential applications to treat burns, gastrointestinal issues, inflammation, and night blindness (Qiu et al. 2002, Senevirathne and Kim 2011). As a terrestrial cyanobacterium, N. commune forms gelatinous colonies composed of vegetative cells, nitrogen-fixing heterocysts, and akinetes (Sand-Jensene 2014). Fig. 2 is the life cycle of cells of Nostoc sp., showing these structures, micrograph imaging, and Nostoc sp in its natural environment.

Figure 2.

Structure of Nostoc sp. (a) The life cycle of Nostoc sp. HK-01 [32], under the Creative Commons license, (b) Light microscopy of Nostoc sp. KNUA003 [33], and (c) N. commune by YAMAMAYA. From Wikimedia Commons (https://upload.wikimedia.org/wikipedia/commons/c/c8/Nostoc_commune.jpg). Licensed under CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0/).

Akinetes are thick-walled resting cells that survive harsh conditions like drought or freezing, and when conditions improve, they germinate back into vegetative cells (Baker and Bellifemime 2000, Perez et al. 2016, Sukenik et al. 2019, Garg and Maldener 2021). Nostoc commune is characterized by spherical, barrel-shaped, or cylindrical cells (Laughinghouse et al. 2019, Singh et al. 2020). The morphological structures of Nostoc species' filament, trichome, vegetative cell, heterocyst, spherical colony, and discoid colony have all been well studied (Briones-Nagata et al. 2007). The thalli of N. commune are encapsulated, containing winding algae filaments, which form a colony of trichomes embedded in a sheath (Wehr et al. 2015). The vegetative cells measure ~4.5–6 μm in length and 5 μm in width (Gao et al. 2024) and are the main photosynthetic cells responsible for growth and colony maintenance (Sand-Jensen 2014). Heterocysts, about 7 μm in diameter and larger than vegetative cells, can be found in the middle or at the ends of the filaments (Diao and Yang 2014). These specialized cells fix nitrogen from the air (N₂) using nitrogenase to a usable form such as ammonia (NH₃), used for growth and other cellular processes (Adams 2000, Kumar et al. 2010). This process allows N. commune to thrive even in environments with low available nitrogen, making them important contributors to nitrogen fixation in various ecosystems (Kumar et al. 2010) especially because nitrogen is a vital nutrient for growth, but most environments have limited usable nitrogen . Its ability to fix atmospheric nitrogen and survive in extreme environments is attributed to various physiological adaptations. One such adaptation is the formation of a protective mucilaginous sheath that shields against desiccation and UV radiation, allowing it to thrive in tough and nutrient-poor conditions (Sand-Jensen 2014, Rastogi et al. 2020). Nostoc commune also forms symbiotic relationships with plants and fungi, providing them with fixed nitrogen in exchange for carbohydrates or other nutrients (Potts 1997). Some strains also produce secondary metabolites, including microcystins, which can be toxic to other organism (Sivonen et al. 1990). These compounds pose potential risks for food and feed applications, underscoring the need for rigorous strain selection, safety assessments, and regulatory oversight. Nostoc commune, like other cyanobacteria, exhibits significant genetic and metabolic diversity driven by adaptation to diverse geographic and environmental conditions, leading to variations in its biochemical composition and bioactivity profiles (Sand-Jensen 2014, Pham et al. 2017, Li and Guo 2018, Wang et al. 2021, Yadav et al. 2022). Such variability offers opportunities for selective breeding or genome-guided cultivation approaches to optimize desired traits.

The evolving phylogeny of Nostoc

The traditional genus Nostoc is not a coherent phylogenetic group and has been a subject of taxonomic refinement in recent years. This is largely due to the advent of molecular technology, which has revealed that the genus, as it was previously defined by morphology, is polyphyletic. This means that the species grouped under Nostoc do not share a single common ancestor. In this review study, we retain the term Nostoc in its broad historical sense for readability, while this section provides an overview of these taxonomic updates.

Molecular studies, which began to challenge the traditional classification (Cordeiro et al. 2020), have been instrumental in splitting Nostoc into multiple genera. For instance, at least eight genotypes of N. commune have been identified based on differences in 16S rRNA gene sequences and other genes like petH and through random amplified polymorphic DNA analysis (Arima et al. 2012). The use of 16S rRNA gene sequences is therefore a key tool in Nostoc reclassification (Strunecky et al. 2023, Pham et al. 2025). As a result, many species once considered part of Nostoc are now placed in new genera within the Nostocaceae family, such as Aliinostoc, Aulosira, and Desmonostoc (Pham et al. 2025). For example, the strain Nostoc linckia was renamed Desmonostoc linckia following these new phylogenetic insights (Hrouzek et al. 2013). The concept that a genus should be monophyletic (descended from a single ancestor) has been the driving force behind this taxonomic update. Some strains previously classified as Nostoc, like Nostoc PCC 7120, are now more accurately classified under the genus Trichormus, specifically as Trichormus sp. PCC 7120. This strain is also known by the name Anabaena sp. (Saraf et al. 2025). Both Nostoc and Trichormus are genera of filamentous cyanobacteria belonging to the order Nostocales (Pratte and Thiel 2021).

While molecular data has clarified many relationships, some challenges remain. The classification of several isolated strains is still pending due to a lack of reference sequences for type species. Future studies will need to use a combination of different molecular markers, such as nifH and Internal Transcribed Spacer sequences, in conjunction with whole-genome sequencing to fully classify these unidentified species (Pham et al. 2025, Marter et al. 2025). Despite the complexities, morphological features still provide a useful initial assessment, but they should be followed by a primary phylogenetic analysis based on 16S rRNA gene sequences to avoid mis-nomenclature (Strunecki et al. 2023). The detailed morphological and 16S rRNA gene sequence data for the new genera will be a valuable reference for future research.

Ecological role and environmental relevance

Habitat, distribution, and associations

Nostoc commune is remarkably adaptable and can be found in various environments worldwide, including freshwater, terrestrial systems, tropical soils, and polar zones (Novis and Smissen 2006, Sakamoto et al. 2019, Jungplut et al. 2021, Yadav et al. 2022, Waditee-Sirisattha and Kageyama 2022). It can grow under carbohydrate-poor conditions, such as limestone pavements, by becoming inactive during dry periods and then reviving when wet conditions return (Yu et al. 2009, Hata et al. 2022). This remarkable adaptability allows it to colonize a wide range of habitats. Despite being a popular edible delicacy regionally, especially in Asia, Africa and South America (Gao 1998), Nostoc can also be a nuisance, causing issues like foul odour in water and affecting the taste and quality of the water (Manganelli et al. 2023).

Nostoc commune interacts mainly with plants, fungi, and protists (Aguilar et al. 2019, Misara and Rakesh 2023) and possibly with algae, sponges and heterotrophic bacteria (Mutalipassi et al. 2021). However, the interaction of N. commune with algae, sponges, and heterotrophic bacteria remains to be extensively explored. In symbiotic relationships, it forms associations with different organisms such as fungi (lichens), liverworts, hornworts, mosses, ferns, cycads, and the angiosperm Gunnera (Adams and Duggan 2008, Carella and Schornack 2018). Consequently, plants must provide a significant amount of the photosynthate for nitrogen fixation to continue (Hungria and Nogueira 2023).

Cyanobacteria such as Nostoc produce toxins that affect animals, likely as an evolutionary response to predation (Ferrao-Filho and Kozlowsky-Suzuki 2011, Holland and Kinnear 2013, Manganelli et al. 2023). Nostoc sp. produces microcystins, which are liver toxins (hepatotoxic) found in various cyanobacteria (Sivonen et al. 1990, Hernandez et al. 2022). This is a concern because of the potential harm these toxins can cause to human and animal health, despite Nostoc being edible. This is evident by the role of microcystin in promoting liver tumours (Gu et al. 2022). Nostoc also forms an unusual endosymbiotic relationship (a rare type of symbiosis where one organism resides within another) with the fungus Geosiphon pyriforme. In this association, Nostoc lives inside the fungal hyphae, and the fungus forms specialized structures called bladders to house the Nostoc filaments (Schlubler 2012). This is likely a beneficial arrangement for both organisms as Nostoc provides the fungus with sugars, and the fungus provides Nostoc with nutrients and protection (Kluge et al. 2003). Studies have shown that some of the carbon dioxide assimilated by Nostoc during carbon fixation is incorporated into the fungi, and Nostoc retains the ability to fix nitrogen as an endosymbiont (Mus et al. 2016). It is important to note that Nostoc’s potential to produce toxins in symbiosis raises important questions about the ecological and health implications of these associations. Comparative studies of toxin profiles across symbiotic and free-living populations remain limited and warrant further investigation.

Contribution to nitrogen fixation and nutrient cycling

Nostoc commune plays a vital role in maintaining soil fertility and nutrient cycling across various ecosystems. As a filamentous cyanobacterium, Nostoc contributes to soil health through several key mechanisms.

As a diazotroph, Nostoc can convert atmospheric nitrogen (N₂) into ammonia (NH₄+), making nitrogen available to itself and other organisms (Imran et al. 2021, Trentin et al. 2023), which is crucial in nitrogen-limited environments. When Nostoc dies and decomposes, the fixed nitrogen is released into the soil or aquatic environment as ammonia, amino acids and proteins, which are usable forms for plants and other microbes (Singh et al. 2016, Grzyb et al. 2021). Through these processes, Nostoc significantly contributes to nitrogen fixation and nutrient cycling, enhancing ecosystem productivity and health.

Nostoc contributes to the soil’s organic matter as it grows and decomposes. This organic matter improves soil structure, water retention, and plant nutrient availability (Obana et al. 2007). Its presence also creates a favourable environment for other beneficial soil microbes. This can further enhance nutrient cycling and overall soil health. For instance, it forms gelatinous colonies that help retain moisture in the soil (Sand-Jensen 2014). It also produces antimicrobial compounds (Vanlalsangi et al. 2022), and since it does not compete aggressively with other microbes for resources (Aguilar et al. 2019), this allows a more diverse microbial community to thrive.

While nitrogen fixation typically occurs during the day through photosynthesis, the study by Hata et al. (2022) studied nitrogen fixation under dark, aerobic conditions. They found that N. commune colonies swelled soon after rehydration (Hata et al. 2022). The study found that colonies rehydrated with glucose showed one-third of the nitrogen-fixing activity of illuminated colonies, suggesting that the cells efficiently catabolized the sugar to obtain the energy needed for nitrogen fixation. This suggests that the processes of rehydration, respiration, photosynthesis, and nitrogen fixation occur in a specific sequence.

Role in ecological restoration, soil stabilization, and carbon sequestration

Cyanobacteria, including N. commune, are among the most ancient groups of biocrusts and play various roles in ecosystem functions, such as enhancing soil structure, stability, fertility, surface hydrology, and soil carbon and nitrogen cycling (Chamizo et al. 2012, Zhao et al. 2014). These photosynthetically active microorganisms can facilitate the re-establishment of biocrusts and may promote seed germination and plant colonization of certain native plant species (Munoz-Rojas et al. 2018). Cyanobacteria produce exopolysaccharides (EPS), which are specialized compounds that contribute to soil aggregation and stability and improve soil water infiltration (Tiwari et al. 2019, Cruz et al. 2020, Larocha 2022, Gracias et al. 2025). They help in retaining soil particles, nutrients, and moisture and also add carbon and nitrogen to the nutrient-poor soils (Kumar and Singh 2020). The recovery of EPS from cyanobacteria is a multistep process. First, the soluble EPS is separated from the cyanobacterial biomass using methods such as centrifugation or membrane filtration (Larocha 2022). A key advantage of this process is that the cyanobacteria often survive the extraction and can be reused to produce more biomass and EPS (Paper et al. 2023). The EPS can then be further purified and processed. It is important to select the right cyanobacterial host and optimize the production process to create an efficient bioprocess (Cruz et al. 2020). Muñoz-Rojas et al. (2018) conducted a study to assess the effects of cyanobacterial inoculation on soil substrates used in dryland restoration, focusing on soil biocrust re-colonization and enhancement of soil health through carbon sequestration. They measured the coverage (%) and photosynthetic biomass of cyanobacteria biocrust on soil substrates inoculated with a consortium of three nitrogen-fixing cyanobacteria strains (N. commune, Tolypothrix distorta, and Scytonema hyalinum) in the resource-rich, biodiverse, semiarid Pilbara region in Western Australia. Hundreds of hectares in the region are disturbed due to established and emerging iron ore mining operations (Erickson et al. 2017). The study showed a positive and rapid effect of inoculated nitrogen-fixing cyanobacteria on the biocrust cover and soil organic carbon levels in post-mining restoration. After 90 days following cyanobacterial inoculation, 30%–40% of the soil surface was covered by biocrust cyanobacteria, and photosynthetic biomass contents increased from 0 to 12.2 μg g⁻¹. During this period, soil organic carbon contents were significantly higher in the inoculated natural soil, topsoil, and waste soil compared to the control (noninoculated) soils. In particular, soil carbon contents increased 3-fold in the mining waste substrate, which initially contained the lowest levels of organic carbon. Soil carbon mineralization rates were generally lower in the inoculated soils, suggesting a stabilization of the accumulated soil carbon. This highlights the potential of cyanobacteria to increase the soil function of reconstructed soils by promoting soil carbon sequestration, and it is safe to assume that N. commune, as a cyanobacterium, will have similar effects. Similar findings were reported in which after three months of incubation in soil, N. commune surface coverage increased up to 36%, and there was no difference between soil inoculated with biomass produced in chemical or fertilizer media. These results demonstrated the potential of N. commune to be economically produced to improve degraded soils.

Potential application in wastewater treatment and pollution control

Biological wastewater treatment is widely used because it effectively breaks down organic matter using microorganisms (Roy and Saha 2021). Compared to physical and chemical methods, it often has lower operating costs (Shankar et al. 2021). However, the initial setup cost for biological treatment can be higher. Using chemicals for wastewater treatment increases the pH, conductivity, and overall load of dissolved matter, resulting in ecological problems (Lenuka et al. 2014). The conventional biological treatment system, through activated sludge, thus appears as the best option. However, this method is limited by the problems relating to dewatering and the disposal of sludge. Hence, the phytoremediation approach has been introduced to address these challenges (Atoku et al. 2021). This approach uses microalgae to reduce the concentrations of hazardous metals in contaminated water (Renuka et al., 2014). Cyanobacteria such as N. commune have extraordinary vitality in urban wastewater, registering faster growth rates and tolerating a wide range of temperatures, pH and high loads of pollutants, making them versatile for sewage purification (Sand-Jensen and Jespersen 2012, Ahmad 2022, Kalita and Baruah 2023). However, it is vital to note that some pollutants, like copper, can harm Nostoc (Cepoi et al. 2022). Azarpira et al. (2014) applied microalgae, N. commune and Oscillatoria limosa to treat sewage water. The study found that the two blue-green algal species have equal potential to remove 83%–98% of Ca 2+, Mg 2+, K+, and Na+. The study conducted by Atoku et al. (2021) applied N. commune, O. limosa, and Chlorella vulgaris to treat the wastewater collected from a rolling mill industry. The study revealed that the three microalgae effectively removed biological and chemical pollutants from wastewater. The removal efficiencies by the microalgae were high for Biochemical Oxygen Demand (BOD), sulphate, chloride, nitrate, and lead (Pb), where more than 70% of the pollutants were successfully phycoremediated. The removal efficiency was very low for copper (Cu), average for cadmium (Cd), and fair for Nickel (Ni), Iron (Fe), and Zinc (Zn). The effectiveness of the microalgae for the removal of metals followed the patterns of Pb > Cd > Ni > Fe > Zn > Cu. We, therefore, recommend the adoption of the three microalgae for the treatment of wastewater before discharge into the water bodies.

Fig. 3 shows a schematic of the impact of the natural by-products of cyanobacteria like N. commune on crops (Ferreira et al. 2023). Nostoc commune demonstrates significant potential for wastewater treatment and pollution control by effectively removing various hazardous metals and pollutants, making it a versatile and cost-effective biological alternative to conventional physical and chemical methods.

Figure 3.

Impact of natural by-products from cyanobacteria such as N. commune on plants

Importance in agriculture

Beneficial effects for crops

Nitrogen-fixing organisms offer a promising solution by forming symbiotic relationships with plants and providing nitrogen in amounts tailored to plant needs, such as in their use as biofertilizers (Chittora et al. 2020). This has gained traction in recent decades, primarily due to their ability to fix atmospheric nitrogen and convert it into a usable form for plants. Cyanobacteria also produce numerous secondary metabolites (carbohydrates, polysaccharides, proteins, vitamins, amino acids, and phytohormones) that promote plant growth and increase disease resistance, reducing biotic and abiotic stress effects (Kumar et al. 2019, Poveda 2021, Nawaz et al. 2024a, 2024b). Modern agriculture depends significantly on nitrogen fertilizers to maintain high crop yields (Spiertz 2010, Govil et al. 2024, Kagan et al. 2024) However, the production and use of these fertilizers contribute to environmental problems, such as releasing harmful greenhouse gases like NO₂, which adversely affect the ecosystem and human health (De-Vries 2021). Only about 50% of the nitrogen fertilizer applied is used by plants, with the rest causing issues like acidification and eutrophication of surface waters (Bijay-Singh and Kraswell 2021, Madjar et al. 2024). Compared to other nutrients, such as basic cations, this nitrogen surplus alters plant tissue composition, reducing their resistance to environmental stress and decreasing plant diversity due to the dominance of fast-growing, nitrogen-loving plants (Vellend et al. 2017, Namuhan et al. 2024). To mitigate these issues, sustainable nitrogen supply methods are being explored. Generally, agriculture’s reliance on nitrogen fertilizers leads to environmental harm, but using nitrogen-fixing organisms like N. commune provides a sustainable alternative by supplying tailored nitrogen, promoting plant growth, and boosting disease resistance.

Impact on soil fertility

Factors such as increased nitrogen content, enhanced organic matter, and improved soil moisture exhibited by N. commune increase soil fertility and improve plant growth. In the absence of nitrogen sources, diazotrophic cyanobacteria can fix atmospheric nitrogen, making it biologically available. This capability distinguishes cyanobacteria from eukaryotic microalgae, as only cyanobacteria can fix nitrogen (Anvarez et al. 2021). Such traits, including desiccation tolerance, are critical for developing bio-soil or biofertilizer, which are valuable, sustainable food production systems in space (space agriculture) (Ahmed et al. 2014). This means that their stress-resilient traits enable them to enhance soil fertility and withstand harsh extra-terrestrial conditions, making them ideal candidates for biofertilizers or bio-soils suitable for crop production in space agriculture. Fig. 4 is an illustration from the study by Arai (2009) showing ecopoisis in Martian Regolith by cyanobacterium, Nostoc sp. HK-01, in Arai’s Mars Eco-systems Dome (A’MED) (Arai 2009).

Figure 4.

Nostoc sp. HK-01, in Arai’s Mars Eco-systems Dome (A’MED) (Arai 2009).

The study by Katoh et al. (2012) isolated N. commune to investigate its agricultural potential. The results suggest that axenically isolated N. commune can be used in space agriculture. The study identified axenic N. commune HK-02 as useful for studying photosynthesis under desiccation using molecular biological analysis and applications in bio-soil and biofertilizer, owing to its nitrogen fixation and desiccation tolerance. This strain of N. commune also demonstrated the ability to detect and adsorb radioisotopes in extreme conditions, such as those in Fukushima, Japan. Fieldwork analysis indicated that soil-adsorbed radioisotopes were the major contaminants trapped by N. commune, while soluble radioisotopes were less significant (Katoh et al. 2012). Soil inoculation with cyanobacteria is a promising technique for reviving degraded drylands because these microorganisms offer several benefits, such as increased soil fertility by nitrogen fixation and helping to bind soil particles together, preventing wind and water erosion (Roman et al. 2018). To fully utilize this biotechnology on a large scale, it must be demonstrated that inoculated cyanobacteria can thrive, improve soil quality, and consistently positively affect degraded dryland soils (Dadzie et al. 2024). Román et al. (2018) studied the effects of inoculating three native nitrogen-fixing species, N. commune, S. hyalinum, and T. distorta, both individually and as a consortium, on soil properties from three different semiarid ecosystems in southeast Spain over 3 months. Their study monitored biocrust colonization by measuring chlorophyll content (a typical surrogate for biocrust biomass). The results showed that all inoculated soils achieved cyanobacteria cover, up to 50%, lower albedo (reflectivity of a surface measured by how much sunlight it can reflect), and higher chlorophyll content. Soil functions were also improved by significantly increasing total organic carbon and nitrogen in all soils.

Application in sustainable farming and organic agriculture

Modern agriculture faces multiple sustainability challenges, including soil degradation, overuse of synthetic fertilizers, loss of biodiversity, and climate change. While chemical fertilizers have significantly increased crop yields, their excessive use leads to soil acidification, nitrogen runoff, and greenhouse gas emissions. Organic farming seeks to reduce these negative impacts, but maintaining soil fertility without synthetic inputs remains a challenge. This is where N. commune plays a crucial role, offering natural nitrogen fixation, soil enrichment, and resilience against desertification. It shows promise for sustainable farming and organic agriculture due to its nitrogen fixation, soil improvement, and combating desertification qualities. The Food and Agriculture Organisation (FAO) of the United Nations projects a need for a 60% increase in global food production to feed a world population of 9.3 billion by 2050. Productivity gains from the ‘Green Revolution’ have plateaued, and limited agricultural land complicates feeding the growing population. Enhancing CO₂ fixation efficiency in crops could significantly boost food productivity per hectare (Parry and Hawkesford 2010, Parry et al. 2011). Future agricultural systems need high productivity with minimal land use and cultivation time. Nostoc commune has gained attention as a viable candidate for its potential in sustainable agriculture, especially due to its activity as a biofertilizer (Pathak et al. 2018). Cyanobacteria-based biofertilizers are cost-effective, costing one-third of chemical fertilizers (Pathak et al. 2018). Nostoc commune helps crops access phosphorus by targeting insoluble organic phosphates. It releases organic acids that break down these complex organic phosphates into simpler forms and excretes enzymes called phosphatases that further convert the simpler organic phosphates into inorganic phosphates readily usable by plants.

Biotechnological application

Production of bioactive compounds

Nostoc commune is known for its capacity to produce a range of bioactive compounds with diverse applications in fields such as medicine, cosmetics, and nutraceuticals. Bioactive metabolites produced by cyanobacteria include indole alkaloids, terpenoids, mycosporine-like amino acids, nonribosomal peptides and polyketides, ribosomal peptides, phenolic acid, flavonoids, vitamins, and antimetabolites (Nandagopal et al. 2021).

Nostoc commune synthesizes several antimicrobial compounds that can kill or inhibit the growth of harmful bacteria. One notable example is noscomin, a diterpenoid. Studies have demonstrated that noscomin exhibits significant antibacterial activity. The study by Jaki et al., as far back as 1999, isolated noscomin from cultured N. commune using bio-guided isolation. They observed antibacterial activity of the isolate against Bacillus cereus, Staphylococcus epidermidis, and Escherichia coli. Nostoc is also a primary producer of certain lead compounds like cytotoxic cryptophycins, antiviral cyanovirin-N, and antitoxic nostocyclopeptides (Fidor et al. 2019). While it shares bioactive peptides with other cyanobacteria, Nostoc often introduces distinct structural modifications. Among these are hepatotoxic microcystins (harmful to the liver) and potent protease inhibitors such as cyanopeptolins, anabaenopeptins, and microginins, which can inactivate enzymes (Janssen 2019, Monteiro et al. 2021). The ability of noscomin to target different bacterial species underscores its potential as a broad-spectrum antimicrobial agent. This could reduce the reliance on traditional antibiotics, thereby mitigating the development of resistance. Understanding the precise mechanisms through which noscomin and other antimicrobial compounds exert their effects is crucial. This knowledge could inform the development of novel antibiotics or enhance the efficacy of existing ones. Also, leveraging biotechnological approaches to mass-produce noscomin could make it a viable candidate for commercial antimicrobial products. Genetic engineering techniques could be employed to optimise the yield of N. commune.

In the study by Shishido et al. (2017), Nostoc sp. CENA543 strain produced new variants of nostamide B–E (2, 4, 5, 6) and namalides D (7), E (9), and F (10) in comparable amounts as the bioactive compound anabaenopeptins (cyclic peptides). This occurs through gene skipping during the active compound biosynthesis. Bioactive peptides from N. commune could be explored for their therapeutic potential in treating conditions like hypertension, where enzyme inhibition is critical. Investigating the structure-function relationship of these peptides could provide insights into their modes of action and lead to the design of synthetic analogues with enhanced efficacy and stability. One challenge is the stability of these peptides in physiological conditions. Research into delivery mechanisms, such as encapsulation or conjugation with other molecules, could improve their stability and bioavailability.

The complex polysaccharides produced by N. commune are being studied for their potential health benefits. These include immune-modulatory effects, antioxidant properties, and possible applications in managing metabolic disorders. In the study by Tamaru et al. (2005), the extracellular polysaccharide of N. commune colonies played a crucial role in enhancing desiccation tolerance, protecting the photosynthetic machinery, maintaining membrane integrity, and improving freeze-thaw tolerance, thus aiding in the survival of the cells under stress conditions. These polysaccharides form a gelatinous layer around the cells, helping retain water, produce oxygen, and offer protection from harsh environmental conditions like drying out (Jasinska et al. 2023). In the study by Jasińska et al. (2023), Nostoc polysaccharide extracts had antioxidant properties, stimulated growth in E. coli, Staphylococcus aureus, and Saccharomyces cerevisiae and had an inhibitory effect on Streptomyces sp. The antioxidant properties of these polysaccharides can help combat oxidative stress, a contributing factor to various chronic diseases such as diabetes, cardiovascular diseases, and cancer. The polysaccharides from N. commune may have prebiotic effects, promoting gut health by stimulating the growth of beneficial gut microbiota. In the study by Li et al. (2022), N. commune Vauch. polysaccharides were broken down by gut microbiota and promoted the growth of beneficial bacteria such as Lactobacillus. This could have far-reaching implications for managing gastrointestinal disorders and enhancing overall health. Further comprehensive studies are, however, needed to fully understand the bioactive compounds produced by N. commune, their mechanisms of action, and their potential applications. Advances in biotechnological techniques can facilitate the large-scale production and commercialization of these compounds.

Potential use in pharmaceutical and cosmeceutical industries

The cosmetic and pharmaceutical industries are experiencing a significant shift towards natural ingredients, driven by consumer demand for sustainable, eco-friendly, and health-conscious products (Nasin et al. 2022, Ratejczak et al. 2023). Nostoc commune fits well within this trend due to its natural origin and multifunctional properties, such as its antioxidant and antiageing properties (Morone et al. 2022). Its use aligns with the clean beauty movement (Santoro 2022), emphasizing transparency, minimalism, and excluding harmful synthetic substances. This trend boosts the marketability of N. commune products and encourages further research and development into its applications.

Nostoc commune, rich in bioactive substances such as polysaccharides, phenols, and flavonoids, contributes to its health benefits. Polysaccharides are known for their moisturizing and antiageing properties, making them valuable in cosmetic formulations aimed at hydration and skin elasticity by promoting collagen production and protecting from UV damage (Maia et al. 2014, Alpuquerque et al. 2022, Yau and Xu 2022, Wu et al. 2024). Phenolic compounds and flavonoids possess antioxidant properties, which protect the skin from oxidative stress and ageing by neutralizing harmful free radicals that damage skin cells and contribute to wrinkles and other signs of ageing (Tungmunnithum et al. 2018, Rahman et al. 2021, Kruk et al. 2022). Pharmaceuticals can also harness these compounds for their anti-inflammatory and antimicrobial effects, offering a natural alternative to synthetic chemicals.

In the study by Tsai et al. (2022), the antiobesity effect of N. commune was demonstrated by its ethanol extract (NEE), which promoted lipid metabolism and inhibited fat accumulation by downregulating adipogenesis-related genes (PPAR-γ, SREBP-1c) and upregulating β-oxidation-related genes (AMPK, CPT-1, PPAR-α), leading to reduced body and fat tissue weight in high-calorie diet-fed rats. In another study, the immunomodulatory effect of N. commune was shown by its polysaccharide-rich extract (NCPS), which activated macrophages, upregulated granulocyte macrophage colony-stimulating factor (GM-CSF) and IL-1β, downregulated IL-6 and IL-17, inhibited the growth of leukemic U937 cells, and induced their differentiation into monocytic/macrophagic lines. Wang et al. (2022) observed a stronger hypoglycaemic activity of N. commune polysaccharide 4 obtained by ultrasonic-assisted extraction (UNCP4) compared to N. commune polysaccharide 3 obtained by heated reflux extraction (HNCP3), suggesting Nostoc’s antidiabetic activity. Xu et al. (2021) showed that N. commune’s antiulcer property was due mainly to its content of p-hydroxybenzaldehyde (HD), a compound that alleviates colitis by reducing inflammation and mucosal injury through downregulating proinflammatory cytokines such as TNF-α and IL-6.

It is interesting to note that N. commune is also important for alleviating stress and improving mental health. In the study by Bahnamiri et al. (2024), N. commune extracts ameliorated schizophrenia-like behaviours, oxidative stress, and inflammation by regulating dopamine levels, enhancing antioxidant defences, and reducing proinflammatory cytokines such as IL-6 and TNF-α in the cerebral cortex of ketamine-induced schizophrenia mice.

Extracts from N. commune may promote wound healing and reduce allergic reactions. Tseng et al. (2021), in an in vitro study, showed that the polysaccharide-rich extract of N. commune promotes collagen I secretion, while inhibiting IL-6 and β-hexosaminidase in cell culture experiments, inferring its wound-healing and antiallergic cosmetics. Collagen I secretion is essential for skin repair and regeneration, and IL-6 and β-hexosaminidase are involved in inflammatory and allergic responses. These reduce inflammation and allergic reactions while supporting skin healing. Further research is, however, needed to confirm its effectiveness in humans. The dual wound healing and antiallergic functionality make N. commune an attractive candidate for developing topical formulations in pharmaceutical and cosmetic products aimed at sensitive or damaged skin.

The term ‘cosmeceutical’ describes cosmetic products bridging the gap between cosmetics and pharmaceuticals (Manel-Azulay and Bagatin 2009, Panday et al. 2024). They contain higher concentrations of active ingredients such as vitamins C and E, peptides (Ngoc et al. 2023), or other substances with targeted effects than typical cosmetics and aim to provide benefits beyond just ‘looking good’, such as reducing inflammation. This can improve overall skin health and address underlying issues.

Nostoc commune holds significant promise for the pharmaceutical and cosmetic industries, driven by its bioactive richness and alignment with current trends towards natural products. Further research is needed to fully harness its potential to standardize extraction methods, ensure safety and efficacy, and optimize production processes. As consumer awareness and demand for natural ingredients grow, N. commune could become a staple in innovative, health-focused product lines. This convergence of natural bioactive potential and market demand positions N. commune as a valuable resource in the future landscape of pharmaceuticals and cosmetics.

Biotechnological exploitation for food and feed purposes

Nostoc commune represents a valuable resource for the future of food and feed industries, aligning with the global shift towards sustainable, nutritious, and environmentally friendly alternatives. Its biotechnological exploitation, backed by rigorous safety measures and regulatory compliance, can pave the way for innovative and health-promoting products in the food and feed sectors.

Nostoc commune’s high protein content of 21.51 ± 0.06% according to the study by Goss et al. (2021) and high fibre content are particularly valuable, offering a sustainable alternative to traditional protein sources (commonly consumed protein sources like meat, poultry, and dairy products) often associated with significant environmental impacts (deforestation, high greenhouse gas emissions, and water use) (Henchion et al. 2017). Additionally, essential vitamins and minerals enhance its appeal as a comprehensive nutritional supplement. This positions N. commune as a viable component in nutraceutical products, addressing global nutritional deficiencies and supporting overall health. The study by Chasquibol et al. (2023) developed a powdered beverage combining protein sources from N. commune and quinoa, demonstrating a balanced profile of essential amino acids according to FAO/WHO standards. The beverage met the standard of the Peruvian health regulations and showed significant nutritional value with high protein content (14.36%), essential amino acids, minerals (potassium, phosphorus, magnesium), vitamins (C and B12), and low heavy metal content, making it a potentially valuable dietary supplement for promoting healthy nutrition, especially in children. This is crucial as nutrition is key to food security and mental well-being (Ejiohuo et al. 2024).

Johnson et al. (2008) analysed N. commune colonies locally consumed in the mountain region of Peru for the presence of neurotoxins. Despite its rich nutritional profile and historical consumption in this region, its utility is tempered by the presence of BMAA, a neurotoxic amino acid linked to neurodegenerative diseases, necessitating careful strain selection and safety assessments for sustainable use. BMAA is a potential environmental risk factor for progressive neurodegenerative disorders such as Amyotrophic Lateral Sclerosis and Parkinson’s Disease (Ra et al. 2021, Lichtfouse et al. 2024, Morris et al. 2025). Epidemiological and bioaccumulation studies have shown a correlation between BMAA exposure and increased incidence of these diseases, suggesting that chronic or repeated exposure could have long-term neurological impacts (Sini et al. 2024). Environmental research has also identified cyanotoxins as potential external triggers in the pathogenesis of these disorders (Sini et al. 2021). Both waterborne and airborne routes have been implicated in human exposure to BMAA and other neurotoxins, raising concerns about their widespread environmental presence and potential health implications. However, it is important to note that the production and quantities of BMAA in cyanobacteria are debatable due to inconsistencies in detection methods, sample preparation, and the difficulty of distinguishing BMAA from its isomers and similar compounds (Wang et al. 2023).

Nostoc commune can be efficiently cultivated, allowing large-scale production in raceway ponds and bioreactors. In the study by Celis-Plá et al. (2021), Nostoc calcicola was cultivated outdoors in thin-layer raceway ponds, where biomass production, physiological status, photosynthetic activity, and biochemical composition were monitored over 5 days and demonstrated increased biomass, maximal quantum yield of Photosystem II (a complex in plant cells and cyanobacteria that helps convert water into oxygen and energy), electron transport rate, photosynthetic efficiency, and antioxidant activity, highlighting its biotechnological potential for producing bioactive compounds (Renger 2012). Advances in cultivation techniques, including controlled environment agriculture, created bioreactors with a tightly controlled environment (light, temperature, CO₂ concentration, humidity, nutrients) which can optimize yield and ensure a consistent supply of high-quality biomass (Dsouza et al. 2023). This scalability is crucial for meeting the growing demand for sustainable and nutritionally rich food sources. Additionally, the resilience of N. commune to various environmental conditions makes it a robust candidate for diverse cultivation settings, further enhancing its appeal for large-scale exploitation.

Traditional and cultural significance

The traditional and cultural significance of N. commune spans various cultures and regions globally. Nostoc commune has been consumed as food for centuries, often incorporated into traditional dishes or used as a supplemental source of nutrition. Its presence in traditional cuisine reflects a deep cultural connection to the natural environment and a reliance on local resources for sustenance.

There is a growing recognition of the importance of preserving traditional knowledge related to biodiversity and food sources, even though not specific to N. commune. Traditional knowledge about harvesting and consuming N. commune can be considered part of this broader effort. Documenting and passing down this knowledge from communities traditionally using N. commune can help ensure its continued use.

Additionally, N. commune holds symbolic value in certain cultures, representing concepts such as resilience due to its ability to thrive in harsh environments, adaptability (reflecting its worldwide presence), and interconnectedness with nature. Its use in traditional medicinal practices and questionable inclusion in rituals and folklore underscores its significance beyond its nutritional value, highlighting its role as a cultural heritage and a symbol of community identity. In European folklore, N. commune, often called ‘star-jelly’ or ‘star-shot’, was believed to be the remnants of shooting stars with special medicinal properties, sometimes used in traditional remedies such as treating puerperal fever (Allen and Hatfield 2004). Overall, N. commune’s traditional and cultural significance underscores its enduring presence as a revered and respected organism in various societies, serving as both a source of sustenance and a symbol of cultural heritage and connection to the natural world.

Challenges and future perspectives

Summary of key challenges

The key challenge bordering N. commune and its effective widespread application, especially in food and biomedicine, is the lack of adequate research on safety and potential side effects. More research is needed to understand its safety and potential fully. Table 1 highlights N. commune’s unique natural advantages (especially terrestrial adaptation and inherent nitrogen fixation), while providing a realistic context of the challenges and opportunities for its broader sustainable integration. The selected cyanobacteria: Spirulina platensis, Anabaena variabilis, Synechocystis sp. PCC 6803, and Synechococcus sp. PCC 7942 were chosen to benchmark N. commune against commercially established strains, nitrogen-fixing peers, and genetically tractable model organisms (Stork et al. 2005, Billis et al. 2014, Zayapan et al. 2014, Blac-Garin et al. 2022, Marquez et al. 2023, Kurpan et al. 2024, Nawaz et al. 2025), enabling a comprehensive evaluation of its biotechnological, ecological, and sustainable development potential.

Table 1.

Nostoc commune and selected cyanobacteria for sustainable applications

Feature/Organism	N. commune (Terrestrial/Freshwater)	Spirulina platensis (Aquatic/Halophilic)	Anabaena variabilis (Aquatic/Freshwater, Filamentous)	Synechocystis sp. PCC 6803 (Aquatic/Freshwater, Unicellular)	Synechococcus sp. PCC 7942 (Aquatic/Freshwater, Unicellular)	Ref.
Growth Form	Macroscopic colonies, gelatinous sheath	Filamentous spirals	Filamentous, heterocyst-forming	Unicellular, coccoid	Unicellular, rod-shaped	[11 186–190]
Habitat	Terrestrial, semi-terrestrial, ephemeral water	Alkaline, brackish/saline lakes	Freshwater, soils	Freshwater	Freshwater	[11 186 188 191 192]
Nitrogen Fixation	Yes (Heterocystous)	No (Requires combined N)	Yes (Heterocystous)	No (Requires combined N)	No (Requires combined N)	[65 188 193–195]
Primary Commercial Use	Traditional food, niche health products, biofertilizer potential	Major food supplement, nutraceuticals, aquaculture feed	Biofertilizer, research model	Research model, potential for biorefineries (engineered for specific products)	Research model, potential for biorefineries (engineered for specific products)	[11 113 186 196 197]
Growth Rate (Relative)	Slow	Very Fast	Moderate	Fast	Fast	[16 193 198–202]
Ease of Cultivation (Scalability)	Challenging for industrial scale, requires specific conditions	High (open ponds, well-established)	Moderate (open ponds, specific nutrient needs)	High (controlled lab/photobioreactor (PBR), genetically tractable)	High (controlled lab/PBR, genetically tractable)	[25 192 193 203–209]
Key Bioactive Compounds (Hong et al., 2018)	Polysaccharides (wound-healing, antiallergic); Mycosporine-like Amino Acids (MAAs) (UV protection, antioxidant); diverse secondary metabolites (antiviral, antitumor, antifungal, antibacterial); proteins, vitamins, minerals.	Phycocyanin (antioxidant, anti-inflammatory); Gamma-Linolenic Acid (GLA); carotenoids (beta-carotene), chlorophyll, high-quality protein, vitamins (B complex, E, K).	EPS; some toxins (e.g. microcystins, anatoxins—strain dependent); enzymes (e.g. phenylalanine ammonia lyase); MAAs, flavonoids, alkaloids.	Primarily a platform for engineered compounds; naturally produces general proteins, lipids, carotenoids (e.g. beta-carotene), and phycocyanin as a photosynthetic organism.	Primarily a platform for engineered compounds; naturally produces general proteins, lipids, carotenoids, and phycocyanin as a photosynthetic organism; model for alkane production.	[9 192 210–222]
Cyanotoxin Production (Known Potential)	BMAA (strain & condition dependent)	Generally considered nontoxic (for certified strains)	Various toxins (e.g. microcystins, anatoxins, saxitoxins—strain dependent)	No (not known as a natural toxin producer)	No (not known as a natural toxin producer)	[8,24 223–230]
Unique Advantages for Sustainability	Terrestrial adaptation (less water-intensive cultivation potential), nitrogen fixation, novel bioactives, resilience to extremes	High protein yield, rapid growth, easy harvest, established market, broad application	Natural nitrogen fixation (biofertilizer), diverse enzyme production	Excellent genetic tractability, model for synthetic biology, efficient CO2 fixation	Excellent genetic tractability, model for synthetic biology, efficient CO2 fixation, hydrocarbon production model	[104 114 115 180 186 204 228 231–238]
Key Challenges for Sustainability	Scalability, variable toxin production, slow growth, complex harvesting	Requires high nutrient inputs, energy-intensive drying	Toxin potential, oxygen sensitivity of nitrogenase, bloom formation in nature	Requires controlled environment, genetic engineering for specific product viability	Requires controlled environment, genetic engineering for specific product viability

Based on Table 1, N. commune stands out as a viable sustainable green microbe due to its unique combination of natural nitrogen fixation, terrestrial adaptation for potentially less water-intensive cultivation, and the production of diverse, valuable bioactive compounds, positioning it as a promising option for sustainable farming (reduced synthetic fertilizer use, soil health), human and environmental health (novel therapeutics, bioremediation), a resilient food source (growth in challenging environments), and a rich subject for research into extreme stress tolerance and unique biochemical pathways. Further research should explore its potential for cultivation and broader use as a food source due to its hardiness, health benefits, and the development of efficient production methods that could increase accessibility.

Despite its promising potential, N. commune faces several significant challenges that require targeted future perspectives to realize its full biotechnological potential. Its slower growth rate compared to commercially dominant cyanobacteria, coupled with complexities in scalable cultivation and harvesting due to its macroscopic, gelatinous morphology, currently limits cost-effective large-scale production; these issues necessitate intensified research into optimized cultivation conditions, such as tailoring light intensity and CO₂ supplementation, and exploring advanced photobioreactor designs, like helical or flat-panel reactors, to enhance biomass density and growth. Furthermore, efficient harvesting could be improved by developing specific methods suitable for its colonial structure, such as auto-flocculation or membrane filtration techniques. Moreover, the variable production of cyanotoxins such as BMAA, which is strain- and condition-dependent, poses a critical safety concern, underscoring the urgent need for stringent quality control measures; this includes rigorous screening and selection of naturally nontoxic strains, implementing precise environmental control during cultivation to suppress toxin biosynthesis, and employing routine analytical testing of harvested biomass.

Addressing the key barriers

To advance the antiobesity and broader therapeutic potential of N. commune from laboratory research to real-world application, a coordinated strategy is required to overcome mechanistic gaps and translational barriers. A foundational step is to deepen mechanistic understanding by elucidating the molecular pathways through which N. commune exerts antiobesity, anti-inflammatory, and immunomodulatory effects. This includes identifying specific bioactive compounds and characterizing their structure-activity relationships, particularly in polysaccharides and pigments, to determine how they influence metabolic, immune, and antioxidant pathways (Mizuno and Minato 2024, Kumar et al. 2025).

Equally critical is improving bioavailability. Many of these compounds have poor absorption and low systemic stability. Nanoencapsulation and lipid-based delivery systems offer promising solutions for enhancing solubility, cellular uptake, and sustained release (Kumar et al. 2025). Optimizing extraction methods to preserve compound integrity is also necessary to maintain therapeutic potency during formulation . To enable large-scale applications, scalability and standardization must be addressed. This includes developing controlled cultivation systems for consistent biomass production, cost-effective extraction and purification protocols, and standardized quality control measures to ensure reproducibility and regulatory compliance. Translational efforts should then move into preclinical and clinical stages, starting with dose–response studies and in vivo safety and efficacy trials. Formulations tailored to various routes of administration (e.g. oral, topical) should be developed, along with studies on drug interactions and long-term safety. For targeted uses such as wound healing, localized delivery systems may further enhance therapeutic outcomes.

Together, these integrated approaches form a comprehensive roadmap for translating N. commune’s promising therapeutic attributes, especially its antiobesity effects, from bench to bedside.

At the farm level, several key barriers hinder the widespread adoption of N. commune as a sustainable biofertilizer. One major challenge is competition with native soil microbiota, as Nostoc must contend with well-established microbial communities for nutrients and space, often leading to poor colonization. In addition, its performance is highly variable across different soil types, particularly between arid and temperate soils, where fluctuations in moisture, temperature, and nutrient availability can significantly impact its growth and nitrogen-fixing capacity.

To overcome barriers such as slow growth rate, systemic scaling challenges, including limited farmer awareness, lack of integration into current agricultural practices, and inadequate infrastructure for large-scale production and distribution (Folina et al. 2025), several practical strategies can be implemented. First, soil preparation techniques that minimize the use of chemical inputs may improve microbial diversity and soil health, creating more favourable conditions for Nostoc colonization . Second, the use of controlled cultivation systems, such as shallow ponds or biofilm reactors, can help optimize environmental conditions such as light, temperature, and nutrient levels to support more robust and consistent biomass production (Novoveska et al. 2023). Site-specific application strategies should also be adopted. These involve tailoring N. commune deployment based on local soil biodiversity, pH, and climate to ensure better adaptation and effectiveness in diverse agricultural settings. Such targeted approaches can enhance establishment rates and increase its usage as a biofertilizer in real-world farming systems.

Although detailed research on the application of advanced technologies specifically to N. commune is still limited, emerging insights suggest promising future directions involving CRISPR gene editing, circular economy integration, and supportive policy frameworks. One approach involves the use of CRISPR/Cas systems to develop enhanced strains of N. commune. CRISPR technology uses synthetic single-guide RNAs that are typically expressed from DNA templates to direct precise gene edits (Gale et al. 2019). In the case of N. commune, this could enable the targeted enhancement of traits such as nitrogen fixation efficiency, resilience to environmental stress, or suppression of unwanted metabolite pathways (e.g. cyanotoxins), making it more suitable for sustainable agricultural and environmental applications.

Another forward-looking approach is the integration of N. commune into circular bioeconomy models. Its natural ability to fix atmospheric nitrogen and adapt to diverse environments makes it well-suited for incorporation into low-input, regenerative agricultural systems. Scalable cultivation technologies such as shallow ponds, photobioreactors, and biofilm-based platforms are already being developed for various cyanobacteria and could be adapted for N. commune (Novoveska et al. 2023).

To ensure the responsible development and deployment of these innovations, robust policy and regulatory frameworks will be essential. Current efforts in microbial biotechnology regulation are focusing on creating guidelines for the safe use of engineered microbes, including CRISPR-edited organisms (Renganathan et al. 2025). These policies must address environmental release protocols, biosafety risk assessments, and usage standards for agricultural or environmental applications. Together, these technological and governance advances could pave the way for sustainable biotechnology solutions, with N. commune playing a key role in climate-smart agriculture, soil health, and ecosystem restoration.

Conclusion

Nostoc commune holds significant promise as a versatile green microbe for sustainable agriculture, health, and environmental applications. Its multifunctionality, ranging from nitrogen fixation and soil regeneration to the production of health-promoting bioactive compounds, positions it as a valuable asset in advancing global sustainability goals. However, realizing its full potential requires overcoming key barriers, including gaps in toxicological data, strain variability, and regulatory uncertainty. Future efforts should prioritize safety validation, strain improvement, scalable cultivation systems, and robust policy frameworks. Integrating emerging tools such as CRISPR gene editing and circular economy models will be critical in transforming N. commune into a safe, effective, and scalable platform for bioinnovation. It is also possible that AI can help accelerate the sustainable development of N. commune by optimizing strain selection, predicting bioactive compound pathways, enhancing cultivation strategies, and guiding safety assessments through data-driven modelling and genomic analysis.

Author contributions

Helen Onyeaka (Conceptualization [equal], Investigation [equal], Methodology [equal], Project administration [equal], Supervision [equal], Validation [equal], Visualization [equal], Writing – original draft [equal], Writing – review & editing [equal]), Adenike Akinsemolu (Investigation [equal], Methodology [equal], Visualization [equal], Writing – original draft [equal], Writing – review & editing [equal]), Abdullahi Idris Muhammad (Investigation [equal], Methodology [equal], Visualization [equal], Writing – original draft [equal], Writing – review & editing [equal]), Ovinuchi Ejiohuo (Investigation [equal], Methodology [equal], Supervision [equal], Visualization [equal], Writing – original draft [equal], Writing – review & editing [equal]).

Conflicts of interest

The authors declare no conflict of interest.

Funding

This study did not receive any grant from funding agencies in the public, commercial or not-for-profit sectors.

Data availability

No new data was generated for this study.