Abstract

Marine cyanobacteria are oxygenic, gram-negative nitrogen-fixing photosynthetic prokaryotes in different environments. It is a universal organism present in aquatic and terrestrial and also extensively scattered in extreme habitats such as hot springs, deserts and glacial environments. Growing concerns over disease outbreaks and other environmental concerns require alternative ways that are economically viable, sustainable, as well as feasible. Recently, cyanobacteria have achieved much consideration because of their potential relevance in various fields, including aquaculture, wastewater treatment, food, fodder, and the production of secondary metabolites, including polysaccharides, vitamins, toxins, enzymes and pharmaceuticals; they also secrete important novel bioactive antimicrobials including antibacterial, antifungal and anti-viral compounds. The emergence of antimicrobial resistance among pathogenic microbes against common antibiotics imposed the search for new antimicrobial agents from natural sources. Various features of cyanobacteria, including their ability to produce novel antimicrobials, make them suitable candidates for their exploitation as a natural source. Hence, this chapter presents an overview of marine cyanobacterial features, antimicrobials isolated from marine cyanobacteria, as well as the mode of action. Among the known cyanobacterial bioactive compounds, many are pharmacologically important and hold immense potential for drug development at the clinical level