Biosynthesis and Characterization of Copper Nanoparticles Using a Bioflocculant Produced by a Yeast Pichia kudriavzevii Isolated from Kombucha Tea SCOBY

Abstract

Over recent years, the ‘green’ chemistry approach to synthesizing nanoparticles has made significant developments. Because of their unique features, nanoparticles have received a lot of attention. The use of a bioflocculant to promote the environmentally friendly synthesis of copper nanoparticles is described in this paper. Copper nanoparticles were biosynthesized using bioflocculant which was produced from a yeast, Pichia kudriavzevii. The chemical reduction approach was used to synthesize copper nanoparticles (CuNPs) using a bioflocculant as a capping agent. Characterization of the as-synthesized copper nanoparticles was conducted using Fourier transform infrared (FT-IR) spectroscopy, UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). The FT-IR spectra revealed characteristic peaks at 3267, 2956, 1656, 1059, and 511 cm−1 for the bioflocculant, while for the bioflocculant passivated CuNPs, the characteristic peaks were at 3482 (-OH), 3261, 1640, 1059, 580, and 519 cm−1 (Cu-O). These peaks revealed that functional groups such as hydroxyls, amines, and copper oxide bonds were present. The UV-Vis analysis showed surface plasmon resonance (SPR) at an absorbance range of 500–600 nm, with peak maxima at 555 and 575 nm for the as-synthesized CuNPs. The XRD pattern revealed planes such as (200) and (220) at 2θ = 43 and 52°, and the particle size (30 nm) was determined by the Debye–Scherrer equation. The transmission electron microscopy analysis revealed a spherical-shaped particle with an average size of 20 nm. The EDX analysis of the as-synthesized CuNPs revealed the presence of the element Cu, which was not present in the EDX image of the bioflocculant used in the synthesis of the CuNPs; this indicated the success of biosynthesis.