Fabrication of silver nanoparticles from marine macro algae Caulerpa sertularioides: Characterization, antioxidant and antimicrobial activity

Green synthesis of metal nanoparticles using marine macroalgae is appealing as it makes use of biomolecules in the extract as individual bioreductant and stabilizing agents. Herein, we report for the first time, the green synthesis of well-stabilized silver nanoparticles (Cs-AgNPs) using Caulerpa sertularioides aqueous extract for application in shrimp aquaculture. The dark brown in the reaction mixture and intense absorbance band at 451 nm in the UV-Visible spectrum provided evidence for the formation of Cs-AgNPs at the optimal conditions (1 mM AgNO3/12 h/pH~11). HR-TEM results revealed that 1 mM of AgNO3 concentration leads to the formation of spherical Cs-AgNPs with an average particle size of 48 ± 4.3 nm in the range of 24–57 nm. In vitro assays demonstrate that Cs-AgNPs had a significant antioxidant and antibacterial activity at 100 and 150 µg/ml respectively. The Artemia nauplii infected with Vibrio harveyi and treated with Cs-AgNPs established the highest survival of 79.00 ± 1.53%. Further, the Litopenaues vennamei infected with White Spot Syndrome Virus (WSSV) and supplementation of 1.5 mg/10 g Cs-AgNPs through feed revealed the highest survival. Overall, the Cs-AgNPs synthesis procedure is convenient and eco-friendly. Further, the microbial results are base for the further large-scale shrimp aquaculture field studies.