ARTP mutagenesis promotes selenium accumulation in Saccharomyces boulardii

Abstract

Atmospheric and room temperature plasma (ARTP) is a rapid method for strain to obtain desirable mutants. In this study, Saccharomyces boulardii was used for mutagenesis through ARTP mutagenesis and the medium for cultivation was further optimized by Box–Behnken design experiments. The biomass of the optimal mutant MSBV reached 42.8 g/L wet cell weight (WCW), and the total selenium (Se) was 13.96 mg/g dry cell weight with the addition of 300 μg/mL of sodium selenite at 0 h medium for 48 h cultivation. In the same conditions, the biomass of wild type (WT) only reached 29.68 g/L WCW, and the Se content was 8.79 mg/g. In addition, MSBV bound to selenium compounds accounted for 76.84% of the total protein, while WT accounted for 79.24%, which was consistent with the energy dispersive spectroscopic analysis. Transmission electron microscopy images of Se-enriched yeast showed that elemental Se0 had a desirable size of approximately 50–200 nm and Se nanoparticles were possibly coated by protein. Therefore, it is worth characterizing the Se nanoparticles and studying the mechanism in the future work. In this study, due to its high Se accumulation and high biomass content, the mutant yeast shows great potential applications in food, medical and pharmaceutic industries.