The arginine deiminase pathway of koji bacteria is involved in ethyl carbamate precursor production in soy sauce

Authors

  • Jiran Zhang,

    1. Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
    2. Synergetic Innovation Center of Food Safety and Nutrition, Wuxi, China
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  • Fang Fang,

    1. Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
    2. Synergetic Innovation Center of Food Safety and Nutrition, Wuxi, China
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  • Jian Chen,

    1. Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
    2. Synergetic Innovation Center of Food Safety and Nutrition, Wuxi, China
    3. National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China
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  • Guocheng Du

    Corresponding author
    1. Synergetic Innovation Center of Food Safety and Nutrition, Wuxi, China
    2. National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China
    3. The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China
    • Correspondence: Guocheng Du, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China. Tel.: +86 510 85918309; fax: +86 510 85918309; e-mails: gcdu@jiangnan.edu.cn

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Abstract

Ethyl carbamate (EC) is a group 2A carcinogen generated from a few precursors in many fermented foods and alcoholic beverages. Citrulline, urea, carbamoyl phosphate, and ethanol are common precursors detected in fermented foods. In this study, citrulline was proved to be the main EC precursor in soy sauce, which was found to be accumulated in moromi mash period and correlated with the utilization of arginine by koji bacteria. Six koji isolates belonging to three genera were identified to be able to accumulate citrulline via the arginine deiminase (ADI) pathway. Among these strains, only Pediococcus acidilactici retained high activities in synthesis and accumulation of citrulline in the presence of high concentration of sodium chloride. These results suggested that P. acidilactici is responsible for the accumulation of citrulline, one of the EC precursors, in the process of soy sauce fermentation.

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