Yeast Enriched with Selenium: A Promising Source of Selenomethionine and Seleno-Proteins

摘要

Organic selenium compound such as selenomethionine plays a significant function in response to oxidative stress. Currently Saccharomyces cerevisiae is one of the best organisms that has ability to accumulate selenomethionine and selenium biotransformation. Addition of mineral selenium to medium culture is a very common practice in order to produce the selenomethionine and Seleno-proteins. Due to the toxicity of selenium for yeasts, selenium tolerant yeast isolation procedures are required. The aim of this investigation was to separate indigenous selenium tolerant S.cerevisiae strains which will not be affected by high selenium concentrations and are able to produce high levels of selenomethionine. In this study, 85 samples were collected from fermentative fruit. Screening was carried out in order to select high yeast cell density and also high selenomethionine accumulation. After confirming yeast strains, selected strains were cultured at a concentration of 25 mg/L sodium selenite and selenomethionine content was measured after 48 hours. The S18 isolate showed had maximum biomass production and selenomethionine accumulation (2655 ppm) and (3.73 g/L) compared to the other isolates. Highlights Selenomethionine is an important amino acid that has a significant role against oxidative stress. Addition of inorganic selenium to the yeast media culture leads to produce the selenomethionine. Saccharomyces cerevisiae is one of the best organisms for selenium biotransformation.