Applications of silver nanoparticles synthesized from Pichia kudriavzevii bioflocculant isolated from Kombucha tea SCOBY

Abstract

Studying the utilization of natural products in the biosynthesis of silver nanoparticles (AgNPs) recently appears to be a fascinating area of research within nanotechnology. These nanoparticles exhibit biocompatibility and inherent stability, making them highly suitable for various industrial applications. The utilization of bioflocculant-synthesized Ag nanoparticles was investigated in this study for the purpose of eliminating diverse pollutants and dyes from wastewater and solutions. In this study, Ag nanoparticles were successfully synthesized through a green method utilizing a bioflocculant derived from Pichia kudriavzevii isolated from Kombucha tea SCOBY as a stabilizing agent. The resulting nanoparticles were then evaluated for their flocculation and antimicrobial properties. Different characterization techniques including SEM, EDX, FT-IR, TGA, and TEM were investigated from the synthesized nanoparticles. Furthermore, the cytotoxicity of the Ag nanoparticles was assessed on human embryonic kidney (HEK 293) cells. The EDX analysis showed elemental Ag constituted 61.93 wt% of the prepared AgNPs. SEM revealed particles with average size of 15.8 nm and were spherical in shape. Thermo-gravimetric analysis (TGA) demonstrated that AgNPs exhibited enhanced thermal stability, retaining over 85 % of their mass at elevated temperatures. In a concentration-dependent manner, the spherical biosynthesized nanoparticles exhibited notable cytotoxic effects on HEK 293 cell lines with over 68 % cell viability at 25 mg/mL concentration. The biosynthesized Ag nanoparticles displayed robust antimicrobial efficacy against both Gram-positive and Gram-negative pathogenic bacteria, though Gram-negative were more susceptible with MIC of 3.125 mg/mL concentration. The nanoparticles showcased a dye removal efficiency exceeding 78 % for all the tested dyes with highest removal efficiency of 96 % for methylene blue at a dosage concentration of 0.2 mg/mL of AgNPs. The Ag nanoparticles exhibited exceptional efficiencies in removing a wide range of pollutants present in wastewater. Compared to traditional flocculants, the biosynthesized Ag nanoparticles demonstrated significant potential in effectively removing both biological oxygen demand (BOD) (92 % removal efficiency) and chemical oxygen demand (COD) (86 % removal efficiency). Thus, the biosynthesized Ag nanoparticles show great potential as a substitute for chemical flocculants in the treatment of industrial wastewater, offering im-proved purification capabilities.