Study of Biosynthesis of Zinc Oxide Nanoparticles Using Issatchenkia orientalis, its Characterization and Application as Antimicrobial and Photocatalytic Agent

Nanoparticles (NPs) exhibit unique physicochemical properties due to their nanoscale dimensions and structural characteristics. In recent years, nanotechnology has transformed the scientific and industrial research. In the present study, we investigated the potential of yeast strains in bio-synthesis of Zinc Oxide nanoparticles (ZnO NPs). Further, we characterized the obtained NPs and evaluated its antimicrobial and photocatalytic potential. The isolates were screened from soil, sea water and bagasse samples, and the most potential isolate was identified as Issatchenkia orientalis based on molecular sequencing. Among the seven isolates obtained in this study, only I. orientalis formed ZnO NPs. Optimum yield of NPs was obtained at room temperature, when the media was supplemented with culture density of 0.8 O.D_540nm and 6% inoculum size, and 60mM ZnSO₄. The NPs were characterized using UV–Vis spectroscopy, FTIR, SEM and particle size analysis. It showed characteristic peaks at 370nm and 380nm in UV-Vis spectroscopy, and between 400 and 700cm^-1 in FTIR analysis. The average size detected was 843.9nm, indicating that the formed particles were nano-clusters. SEM analysis further confirmed the biosynthesis of irregular NPs. The NPs showed moderate antibacterial activity, with maximum efficacy observed against Bacillus subtilis. The NPs were also capable of photocatalytic degradation of Congo red dye, which is a toxic industrial pollutant. A degradation efficiency of 54.68% was achieved within 120 mins. Overall, this study demonstrates controlled bio-synthesis of ZnO NPs and paves the way for developing efficient and sustainable solutions for environmental and biomedical applications.