Biosynthesis of Silver Nanoparticles Using Two Seaweeds and Their Potential Towards Environment

Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine.Biologically synthesized silver nanoparticles have a wide range of applications. The biosynthesisof silver nanoparticles is an eco-friendly method in the field of nanotechnology. Seaweed extractsof Caulerpa racemosa (Forsskål) J. Agardh and Ulva lactuca Linnaeus was used as a reducing agentin the eco-friendly extracellular synthesis of silver nanoparticles from an aqueous solution of silvernitrate (AgNO3). High conversion of silver ions to silver nanoparticles was achieved with Ulva lactucaat reaction temperature of 100 °C and a seaweed extract concentration of 10% with a residential timeof 1 h using reflux extractor when compared with the other methods. Formation of silver nanoparticleswas characterized by spectrophotometry and the electron microscopic technique. The averageparticles size was ranging from 35 to 75 nm. Antimicrobial activities indicate the minimum inhibitoryconcentration of biologically synthesized nanoparticles tested against the pathogen Staphylococcusaureus (1 mg/ml). High inhibitions over the growth of Pseudomonas aeruginosa, Vibrio cholerae andEscherichia coli were witnessed against the concentrations of 1 mg/ml. Enzyme assay of the collectedseaweeds performed using standard protocol to assess the potency level. Further, seed germinationtest proved that synthesized nanoparticles were environmentally safe, for which the same can be usedfor effluent treatment process.