Screening of Selenium-enriched Yeasts with Enhanced Aroma and High Alcohol Production by ARTP Mutagenesis

In order to obtain endophytic selenium-rich yeast from Lycium barbarum with strong ability producing alcohol and aroma, and then promote the selenium-rich fermentation products and improve the flavor, this study took the endophytic yeast of L. barbarum stored in the laboratory as experimental materials, and the yeast with strong selenium-rich ability was obtained through the initial screening of selenium-resistant method and red selenium methods. Atmospheric room temperature plasma (ARTP) technology was used to obtain mutant strains and through TTC medium, Duchenne tubule fermentation, alcohol production, ester and acid production, tolerance and other experiments to screen out the target strains of aroma enhancement and high alcohol production. The content of selenium in yeast cell and fermentation liquid was determined by hydride generation atomic fluorescence spectrometry. The results showed that M1 Saccharomyces cerevisiae and M16 Clavispora lusitaniae were obtained by primary selenium screening, the mutagenic strain M1-5 of S. cerevisiae with higher alcohol production capacity and the mutagenic strain M16-28 of C. lusitaniae with higher aroma production capacity were obtained through ARTP mutagenesis. The alcohol production capacity of M1-5 increased by 38.07% compared with M1, and the ester production capacity of M16-28 increased by 107.62% compared with M16, and the genetic stability was good. The selenium contents in the intracellular and fermentation broth of the M1-5 strains were 204.8 and 1158 μg/L, respectively, and in M16-28 were 666.45μg/L and 1830 μg/L, respectively. Therefore, the selenium enrichment capacity of M16-28 was higher than that of M1-5, and the selenium content of fermentation liquid was extremely significantly higher than that of yeast cells (P<0.001). In conclusion, the selenium-rich yeast with mutagenic strain M1-5 producing alcohol and M16-28 producing aroma were screened out, which had excellent fermentation characteristics and potential application prospects in the development and mining of fermented food and selenium-rich functional products.