Production of Zinc-Yeast from Saccharomyces cerevisiae Fermentation and Determination of Zinc Content by Atomic Absorption Spectrophotometry
Objectives: This study aimed to obtain an optimum method for zincyeast production. Materials and Methods: Production of zinc-yeast was prepared using Yeast Extract Peptone Dextrose (YEPD) as a culture medium. Yeast that had been inoculated into culture media was incubated with a shaker at room temperature for 84 hrs, then zinc sulfate was added with various concentrations of 200, 300, and 400 mg/L, and then incubation continued for 24 hrs. The obtain yeast biomass was dried with a Freeze-dryer and analyzed for total accumulated zinc and protein content. Determination of zinc was using atomic absorption spectrophotometry (AAS) at a wavelength of 196 nm, whereas protein content was determined with Bradford method at a wavelength of 595 nm using UV-Vis spectrophotometer. Results: Zinc-yeast with the addition of 200 mg/L zinc sulfate obtained 0.3111 g that contains 2228.60 μg/g of zinc and 0.8515 mg/L of protein. While zinc-yeast with the addition of 300 mg/L zinc sulfate obtained 0.3704 g that contains 2458.30 μg/g of zinc and 0.8682 mg/L of protein. And the last, zinc-yeast with the addition of 400 mg/L zinc sulfate obtained 0.2370 g that contains 2648.43 μg/g of zinc and 0.8935 mg/L of protein. Conclusion: Production of zinc-yeast with the highest zinc and protein content can be obtained by adding 400 mg/L zinc sulfate solution to the stationary phase culture of S. cerevisiae. The modified zinc-yeast production method is simple and can be used for the production of functional food products.