Biogenic synthesis of zinc oxide nanoparticles using Pichia cactophila-derived β-glucan as a novel capping agent: Characterization, antioxidant, antibacterial, and cytotoxicity evaluation.

The present study reports the isolation and molecular identification of Pichia cactophila JP strain from Jogimatti Forest soil, Karnataka, India, and the first-ever use of its extracted β-glucan as a biogenic capping agent for ZnO nanoparticle synthesis. β-glucan was isolated via acid-alkali extraction (yield: 4.6% w/w dry cell weight) and employed in a co-precipitation method to synthesize YGZnNP-1. Physicochemical characterization confirmed a crystalline hexagonal wurtzite ZnO structure (JCPDS No. 36-1451), an average crystallite size of ∼28.5 nm, and a UV absorption peak at 372 nm. FTIR spectroscopy verified effective β-glucan surface functionalization. YGZnNP-1 exhibited potent dose-dependent antioxidant activity (DPPH IC50: 79.73 μg/mL), significant antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus, and favourable biocompatibility against NIH 3T3 fibroblast cells (IC50: 98.20 μg/mL). These findings establish YGZnNP-1 as a promising multifunctional nanomaterial for biomedical applications.