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

Xujun Chen; Shuyi Li; Xin Cong; Tian Yu; Zhenzhou Zhu; Francisco J Barba; Krystian Marszalek; Czesław Puchalski; Shuiyuan Cheng

doi:10.3389/fnut.2020.543873

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

Front Nutr. 2020 Nov 5:7:543873. doi: 10.3389/fnut.2020.543873. eCollection 2020.

Authors

Xujun Chen¹, Shuyi Li¹, Xin Cong^{1

2}, Tian Yu^{1

2}, Zhenzhou Zhu¹, Francisco J Barba³, Krystian Marszalek^{4

5}, Czesław Puchalski⁶, Shuiyuan Cheng¹

Affiliations

¹ National R&D Center for Se-rich Agricultural Products Processing, College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan, China.
² Enshi Se-Run Health Tech Development Co., Ltd, Enshi City, China.
³ Nutrition and Food Science Area, Department of Preventive Medicine and Public Health, Food Science, Toxicology and Forensic Medicine, Faculty of Pharmacy, Universitat de València, Avda. Vicent Andrés Estellés, València, Spain.
⁴ Department of Fruit and Vegetable Product Technology, Prof. Wacław Dabrowski Institute of Agricultural and Food Biotechnology, Warsaw, Poland.
⁵ Department of Chemistry and Food Toxicology, Institute of Food Technology and Nutrition, College of Natural Sciences, University of Rzeszów, Rzeszow, Poland.
⁶ Department of Bioenergetics, Food Analysis and Microbiology, Institute of Food Technology and Nutrition, College of Natural Sciences, University of Rzeszów, Rzeszow, Poland.

Abstract

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, Bacillus cereus, an important probiotic, was used for selenium enrichment with sodium selenite as selenium source. The growth curve of B. cereus was investigated, and 150 μg/ml was selected as the concentration of selenium for B. cereus 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.

Keywords: Bacillus cereus; fermentation; organic selenium; response surface methodology; selenium enrichment.