Denitrifying halophilic archaea derived from salt dominate the degradation of nitrite in salted radish during pickling. (February 2022)

• Record Type: Journal Article
• Authors: Wei, Wei; Hu, Xinyu; Yang, Sai; Wang, Kaili; Zeng, Chunlin; Hou, Zhaozhi; Cui, Henglin; Liu, Shenkui; Zhu, Lin
• Is Part Of: Food research international. Volume 152(2022)
• Publication Date: 2022-02
• Subjects: Salted radish -- Nitrite degradation -- Halophilic archaea -- Truncated denitrification; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2021.110906
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Nitrite generated during salted radish pickling can be naturally degraded. Microbial denitrification, not chemical reaction, induces nitrite degradation. Denitrifying halophilic archaea derived from salt dominate such nitrite degradation. Halophilic archaea reduced NO2 − to N2 via truncated denitrification in salted radish. Abstract: Salted radish is a popular high-salinity table food in China, and nitrite is always generated during the associated pickling process. However, this nitrite can be naturally degraded, and the underlying mechanism is unknown. Here, we identified the microbial groups that dominate the natural degradation of nitrite in salted radish and clarified the related metabolic mechanism. Based on dynamic monitoring of pH and the concentrations of nitrogen compounds as well as high-throughput sequencing analysis of the structural succession of microbial communities in the tested salted radish, we determined that the halophilic archaea derived from pickling salt dominate the natural degradation of nitrite via denitrification. Based on isolation, identification, nitrite reduction assays, and genome annotation, we further determined that Haloarcula, Halolamina, and Halobacterium were the key genera. These halophilic archaea might cope with high salt stress through the "salt-in" mechanism with the assistance of the accumulation of potassium ions, obtain electrons necessary for "truncated denitrification" from the metabolism of extracellular glucose absorbed from salted radish, and efficiently reduce nitrite to nitrogen, bypassing nitrite generation from nitrate reduction. The present study provides important information for the prevention and control of nitrite hazards in salted vegetables with high salinity, such as salted radish.