Department of Botany, North Orissa University, Baripada - 757003, Odisha, India. *Corresponding author: E-mail: skmrbhakta@gmail.com 2 Microalgae: A Potential Source of Bioactive Metabolites S. BHAKTA, E. SAHU AND A.K. BASTIA* ABSTRACT Microalgae, more specifically cyanobacteria, produce a wide array of compounds with biological activity. These include antibiotics, algaecides, toxins, pharmaceutically active compounds and plant growth regulators. Recently, microalgae have become targets for screening programmes in search of novel compounds of potential medicinal value. Secondary metabolite production by microalgae varies with environmental conditions. When these processes are better understood, microalgae might become economic sources of new drugs and other structurally specific chemicals because production can be optimized in controlled culture. Secondary metabolites from microalgae comprise a variety of substances. The chemicals involved are mostly unidentified and needed to explore for human welfare. In this review an attempt has done to through light on important bioactive compounds such as carotenoids, micosporin like aminoacids, phycocolloids, lectins, halogenated compounds, fatty acids, sterols, polyketides and other compounds used frequently for pharmaceuticals. Key words: Microalgae, Cyanobacteria, Bioactive metabolites INTRODUCTION The use of natural bioactive compounds as a source of remedies for treatment of disease till date is well realized despite of the significant contribution of synthetic drugs to modern pharmaceuticals. The growing evidence of acquired resistance by target species with consequent implications for both cost and