Optimization of culture parameters of selenium-enriched yeast (Saccharomyces cerevisiae) by response surface methodology (RSM)

Effect of culture conditions (temperature, initial pH value and volume) on the bioaccumulation of selenium (Se) in yeast (Saccharomyces cerevisiae) were investigated by response surface methodology (RSM) in this paper. The combined effects of culture conditions on Se yield were studied using a three-level three-factor Box–Behnken design. Fermentation was carried out at different temperature (24–32 °C), initial pH value (4–7) and volume (40–100 mL). The results showed that the optimum conditions for Se enrichment of yeast were found at temperature 27.4 °C, initial pH value 5.8 and volume 89.4 mL. Total Se yield was significantly affected by culture temperature (P < 0.05), initial pH value (P < 0.01) and volume (P < 0.01).Using a culture medium supplemented with 15 μg/mL sodium selenite (Na2SeO3) added at 9 h after inoculation which is the logarithmic growth phase, the maximum biomass and total Se yield in yeast could reach 9.23 g/L and 5.90 mg/L, respectively, which were significantly higher (P < 0.05) than that of the control (8.82 g/L and 4.31 mg/L)