eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2014-04-28 11 1 6431 article J. Saraniya Devi 1 B. Valentin Bhimba 1 Department of Biotechnology, Sathyabama University, Rajiv Gandhi Salai, Chennai - 600 119, India. In this study silver nanoparticles (AgNPs) were synthesized using a marine macro red algae-Hypnea muciformis. To the algal extract 1mM aqueous silver nitrate was added and exposed to 121ºC for 10 mins. The synthesized AgNPs were characterized by observing a peak at 429nm using UV-visible spectroscopy. Antibacterial activity was investigated against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa. The synthesized AgNPs were found to possess discrete antibacterial activity at a concentration of 5μl/ml. AgNPs exhibited more activity than silver nitrate (control) and standard antibiotic ampicillin. Antifungal activity against Candida albicans, Candida parapsilosis and Aspergillus niger was investigated along with standard control, Nystatin. The synthesized AgNPs exhibited a potent antifungal activity against tested fungal strains. Results of this study indicated that AgNPs have remarkable potential as an antimicrobial agent in treating infectious diseases. https://www.biotech-asia.org/vol11no1/antibacterial-and-antifungal-activity-of-silver-nanoparticles-synthesized-using-hypnea-muciformis/ Marine macro red algae-Hypnea muciformis; AgNPs; UV Vis; Antibacterial; Antifungal