AUTHOR=Chen Xujun , Li Shuyi , Cong Xin , Yu Tian , Zhu Zhenzhou , Barba Francisco J. , Marszalek Krystian , Puchalski Czesław , Cheng Shuiyuan 

TITLE=Optimization of Bacillus cereus Fermentation Process for Selenium Enrichment as Organic Selenium Source

JOURNAL=Frontiers in Nutrition

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2020.543873

DOI=10.3389/fnut.2020.543873

ISSN=2296-861X

ABSTRACT=<p>Selenium is an essential trace element and micronutrient for human health. Application of organic selenium in plants and microorganisms as trace element supplement is attracting more and more attention. In this study, <italic>Bacillus cereus</italic>, an important probiotic, was used for selenium enrichment with sodium selenite as selenium source. The growth curve of <italic>B. cereus</italic> was investigated, and 150 μg/ml was selected as the concentration of selenium for <italic>B. cereus</italic> fermentation. With application of response surface methodology, the optimal fermentation conditions were obtained as follows: inoculation quantity of 7%, culture temperature of 33°C, and shaking speed of 170 rpm, leading to the maximal selenium conversion ratio of 94.3 ± 0.2%. Field emission scanning electron microscope and energy dispersive spectrometry evidenced that inorganic selenium had been successfully transformed. This study may contribute to get a strain with high Se conversion ratio, so as to extract organic selenium in the form of selenoprotein to be used for further application.</p>