Integrated metatranscriptomics and metabolomics revealed the metabolic pathways of biogenic amines during Laotan Suancai fermentation

Laotan Suancai is a popular traditional Chinese fermented vegetable with a unique flavor. Current studies have focused on revealing the relationship between microbiota and flavor. However, the metabolism of biogenic amines (BAs), an important harmful substance, by the microbiota during Laotan Suancai fermentation remains unclear. In this study, we investigated the dynamic changes of eight BAs during the fermentation. The primary BAs, putrescine and cadaverine, reached 45.96 ± 3.01 mg/kg and 43.10 ± 2.37 mg/kg, respectively, at the end of fermentation. Spearman correlation analysis revealed significant correlations between BAs and 15 different species. Besides, the metabolic pathways of BAs were reconstructed via metatranscriptome and metabolome analyses. BAs. Furthermore, key microbes involved in BA metabolism in Laotan Suancai, such as Lactobacillaceae species, Picha, and Tetragenococcus halophilus, were identified. These findings improve our understanding of BA metabolism in fermented vegetables and have implications for the development of starter cultures with the ability to degrade BAs in the industrial production of Laotan Suancai.