Preparation of Organic Selenium Yeast by Fed-Batch Fermentation

Selenium is highly proper prepare essential element for the development of mammals and its incorporation in yeast could serve to Selenium enriched yeast. Production of Selenium (Se) enriched yeast was studied by fed-batch fermentation technology using synthetic nutrients to minimize the influence of sulfur and glucose used as the carbon sources. The effect of Selenium (Se) on yeast growth was also evaluated by employing. Se-adapted yeast cultures in continuous fermentation. Fedbatch fermentation with a total of 100 ppm of Sodium selenite in the medium (Na2SeO3), yielded 32.09 g L−1 of dry yeast cell biomass containing 3758 ± 6.5 ppm of organic Se. The resultant product had the Methylene Blue Reduction Test (MBRT) timing of > 25 min, indicating the highest accumulation of organic Se. The elemental analysis showed the sulfur content was reduced by 37% in selenium yeast (Se-yeast) than the normal yeast produced without Se supplementation. There was a reduction in the experimental biomass yield of Se-yeast by 18 g L−1 than the theoretical biomass yield in response to the Se addition. A morphological analysis of the normal and Se enriched yeast cells using scanning electron microscopy indicated a reduction in cell size by 0.88 μm in response to Se supplementation.