BIOLOGICAL SYNTHESIS. In recent years, green synthesis has attracted increasing attention as a simple, fast, cheap, and environmentally friendly method that uses non-toxic solvents and produces fewer harmful by- products.142 The synthesis of metal nanoparticles comes from a variety of biological sources, including plant extracts, enzymes, and microorganisms, which can act as reducing, stabilizing, and coating agents for nanoparticle biosynthesis as a new method without environmental concerns and limited clinical applications. In this context, studies on a variety of different microorganisms such as bacteria, yeast, and fungi have shown that yeast has the advantages of high tolerance to metal ions and high metal production, making it a good candidate for nanoparticle synthesis. Enzymes are highly produced substances and their ability to bioaccumulate metals on bacteria.143-144 As a probiotic microorganism, the yeast Saccharomyces cerevisiae belongs to the division Ascomycota and the class Saccharomycetes.145 Commonly known as 'brewer's yeast' or 'baker's yeast', S. cerevisiae is widely used in the brewing and baking industries.146 In particular, it has been approved as safe by the FDA and is used as a biotherapeutic agent.147,148 In addition, S. cerevisiae has excellent enzymatic activities, making it of great value in the food and pharmaceutical sectors.149 This non-pathogenic yeast is easily accessible and contains many bioactive compounds, including proteins and enzymes, that are useful for the environmentally friendly synthesis of nanoparticles. Sriramulu and Sumathi150 conducted a study in which they used S. cerevisiae as a sequestering and reducing agent in a simple and inexpensive method to produce palladium nanoparticles. The synthesis process involves several steps, which are described in detail in the Materials and Methods, section 4.4. In this discussion, the samples will be referred to as ZnO (N_CFE), ZnO (A_CFE), and ZnO (Cl_CFE), indicating the specific precursors used (nitrate, acetate, and chloride) and the inclusion of brewer's yeast in the synthesis. The corresponding control samples are labelled as ZnO (N), ZnO (A), and ZnO (Cl). The samples labeled ZnO (N_CFE_WL), ZnO (A_CFE_WL), and ZnO (Cl_CFE_WL) correspond to the synthesis process carried out with three different precursors, together with the inclusion of a brewer's yeast solution and exposure to white light irradiation. The corresponding control samples are designated ZnO (N_WL), ZnO (A_WL), and ZnO (Cl_...
