CHLORELLA MINUTISSIMA AS A FUNCTIONAL FOOD AND BIO-NANO FACTORIES FOR SILVER NANOPARTICLE SYNTHESIS, CHARACTERIZATION AND APPLICATIONS

Abstract

Chlorella minutissima acts as a functional food due to the presence of various nutraceuticals such as beta-carotene. Beta-carotene extracted from algal sources are sustainable and economical for use and large-scale production. Beta-carotene helps in prevention of various diseases by acting as an antioxidant. Apart from acting as a functional food, Chlorella minutissima also acts as bio-nano-factories for the synthesis of silver nanoparticles. This approach of synthesis of silver nanoparticle is green, ecofriendly, low-priced biotechnological approach that gives advancement over both chemical and physical methods. In the current study, an aqueous extract of C. minutissima fresh biomass was used for the green synthesis of Ag-NPs, since C. minutissima extract plays a dual part in both reducing and stabilizing Chlorella-silver nanoparticles (C-AgNPs). The UV-Visible absorption spectrum, fourier transforms infrared, X-ray diffraction, zeta-potential and field emission-scanning electron microscope were performed for confirming and characterizing the biosynthesis of C-AgNPs. FE-SEM images depicted the spherical Ag-NPs shape. FT-IR analysis demonstrated the presence of free amino groups in addition to sulfur containing amino acid derivatives acting as stabilizing agents as well as the presence of either sulfur or phosphorus functional groups which possibly attaches silver. XRD pattern depicted that the biogenic Ag-NPs were crystalline in nature with FCC structure. Zeta potential analysis relieved that the C-AgNPs are highly stable with an average size of 78.28 nm. In this study, synthesized Ag-NPs exhibited strong antibacterial activity against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Salmonella sp., and Klebsiella sp. C-AgNPs have demonstrated a removal efficiency of 76.07% for Chromium and 99.71% for Nickel at pH 3. C-AgNPs have been demonstrated to show 82.34% photocatalytic dye degradation efficiency for methylene blue. Thus, it can be concluded that Chlorella minutissima is a potential microalgae agent for synthesis of silver nanoparticles having antibacterial potential, adsorption of heavy metals, and photocatalytic dye degradation. It will be sustainable approach to deal with environmental pollution and combat antimicrobial resistance.