Enhancing Selenium Accumulation in Rhodotorula mucilaginosa Strain 6S Using a Proteomic Approach for Aquafeed...

Area of Science:

• Biotechnology
• Microbiology
• Nutritional Science

Background:

• Selenium (Se) is an essential trace element vital for fish growth and biological functions.
• Selenium protects biological components like DNA, proteins, and lipids from oxidative damage.

Purpose of the Study:

• To optimize selenium accumulation in the native yeast *Rhodotorula mucilaginosa* 6S.
• To analyze the effects of sodium selenite, nitrogen sources, and pH on yeast growth and Se accumulation.
• To evaluate the yeast proteome under different cultivation conditions.

Main Methods:

• Evaluated sodium selenite concentrations (5-40 mg/L).
• Analyzed nitrogen sources and pH effects on cell growth and Se accumulation.
• Scaled up optimal conditions to a 2 L bioreactor and performed proteomic analysis.

Main Results:

• Optimal conditions for biomass and Se accumulation were identified as ammonium chloride and pH 5.5.
• Cultivation with 30 mg/L sodium selenite yielded 10 g/L biomass with 0.25 mg Se/g, containing 25% protein, 15% lipids, and 0.850 mg carotenoids/g.
• Proteomic analysis revealed 1871 proteins, with selenium influencing catalytic and oxidoreductase activities.

Conclusions:

• *Rhodotorula mucilaginosa* 6S is a viable source for producing selenium-rich biomass.
• The biomass is also rich in proteins, lipids, and pigments, beneficial for aquaculture.
• Selenium exposure modulates yeast proteome, impacting key metabolic activities.