Abstract:
This study aimed to breed the saccharomyces cerevisiae strain that could efficiently use the purple sweet potato powder as the nutrient source and enrich the selenium by ARTP mutagenesis technology, in order to develop the new selenium-enriched purple sweet potato yeast products and promote the high-value and diversified utilization of purple sweet potato raw materials. By taking the saccharomyces cerevisiae CICC-1015 as the original strain, and using the ARTP mutagenesis combined with the selenium tolerance gradient acclimation screening, the yeast mutant strain was selected which could grow in the medium containing purple sweet potato powder, and could tolerate the higher concentrations of sodium selenite and efficiently biotransform into the organic selenium. The results showed that the strain cultured for 16 h was used as the original strain for mutagenesis. The ARTP treatment time was 110 s, and the lethality reached 94.2%, which could not only maintain the high mutation frequency, but also help to screen the beneficial mutant strains. The mutant strain FJH-010 with the highest tolerance to 200 mg·L
−1 sodium selenite was screened. The mutant strain could grow well in the environment with 10% purple sweet potato powder as the raw material, with the biomass reaching 20.6 g·L
−1 (dry weight), and the selenium content reaching 4245 μg·g
−1. Among them, the proportion of organic selenium was 95.3%, the transformation rate of selenium reached 95.8%, and the genetic stability was good, showing the strong selenium enrichment and transformation ability, which would provide a new approach for the further development of the selenium-enriched purple sweet potato yeast products containing the organic selenium.