Keratinase-Mediated Zinc Oxide Nanoparticles from Poultry Feather Waste Valorization: Characterization, Stability and Reusability

Abstract

The principles of green technology emphasize sustainable, energy-efficient, and environmentally benign processes that minimize chemical waste while maximizing resource recovery. Within this paradigm, nanoparticles-based formulations have emerged as synergistic strategies to enhance industrial biocatalysts. Nanoparticles approaches improve enzyme utilization by confining enzymes or microbial cells within a distinct phase, while still permitting free diffusion of substrates and products. Among biocatalysts, keratinase has become pivotal for waste valorization and circular bioeconomy applications. Enabling repeated catalytic cycles can reduce costs and improve efficiency and reusability. The present study shows the results of keratinase zinc nanoparticles synthesis, characterization, and reusability capacity. Characterization studies included UV-visible spectroscopy, Fourier- transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Dynamic light scattering (DLS), and scanning electron microscopy (SEM) analysis. The keratinase-assisted KZnNPs synthesis follows similar green-friendly routes, producing nanoparticles with more stability and industrial applicability. Enzyme activity remained maximum up to 12 consecutive batches of feather degradation. The keratinase zinc nanoparticles were reused up to six cycles with 67.11% residual activity, while 53.6% activity was retained till the 12th cycle. This is crucial for industrial use as it decreases expenses and boosts efficiency. This biogenic pathway avoids hazardous reducing agents, ensuring safer, sustainable production while maintaining catalytic activity. These innovations enhance enzyme stability, reusability, and catalytic efficiency, while valorizing keratin-rich waste into valuable products, Such as amino acids, peptides, biofertilizers, and bioplastics. Overall, keratinase-mediated ZnO nanoparticles demonstrate a promising role in feather waste valorization, enabling eco-friendly, cost-effective applications across environmental and industrial domains.