Antibacterial activity of freshwater microalgae: A review

The photoautotrophic microorganisms collectively termed ‘micro-algae’ (including micro-eukaryotes and cyanobacteria) are known to produce a wide range of secondary metabolites with various biological actions. They are known as well for their richness in bioactive compounds, with promising applications in pharmaceutical formulations. Their cell-free extracts have accordingly been tested as additives for food and feed formulation, in attempts to circumvent use of antimicrobial compounds of synthetic origin, or subtherapeutical doses of regular antibiotics. The increased use of antibiotics and chemotherapeutants for disease treatment leads to emergence of drug resistant forms. It also adversely affects the ecosystem. Microalgae are rich source of antimicrobial agents and provide a safer and cost effective way of treating bacterial infections. This article describes the antibacterial properties of some freshwater microalgae like, Euglena, Microcystis, Chlorella, Chroococcus, Anabaena, Oscillatoria and Spirulina.   Key words: Antibacterial, Aeromonas hydrophila, bioactive compounds, extraction, Euglena viridis.