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

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.