Novel Insight into Metabolism Mechanism of Biogenic Amines During Fermentation of Chinese Traditional Fermented Mandarin Fish (Chouguiyu) Based on Metabolism Pathway and Correlation Network

A complex microbial community gives the possibility to produce biogenic amines in traditional fermented foods. In this study, the metabolism mechanisms of biogenic amines during fermentation of fermented mandarin fish <i>Chouguiyu</i> were revealed based on the metabolic pathways and correlation analysis. Functional genes based on KEGG orthology related to biogenic amine metabolism were selected from the metagenome and were used to construct the biogenic amine metabolic pathways in <i>Chouguiyu</i>. A total of 91 and 75 genera were related to the synthesis and degradation of biogenic amines, respectively. High concentrations of cadaverine and putrescine were observed, while the other biogenic amines were detected in relatively low concentrations. The metabolic mechanisms of various biogenic amines were illuminated by correlation network maps between biogenic amines and microbial synthesis/degradation enzymes. <i>Lactococcus</i>, <i>Flavobacterium</i>, <i>Tessaracoccus</i>, and <i>Yoonia</i> could only degrade and not produce biogenic amines. <i>Acinetobacter</i> and <i>Enterococcus</i> possessed more abundant enzymes for degradation than synthesis. Amine oxidase (K00276), diamine N-acetyltransferase (K00657), and gamma-glutamylputrescine synthase (K09470) were the main biogenic amine degradation enzymes in the microbial community. <i>Lactococcus garvieae</i>, <i>Flavobacterium gelidilacus</i>, <i>Tessaracoccus antarcticus</i>, <i>Yoonia vestfoldensis</i>, <i>Acinetobacter haemolyticus</i>, and <i>Enterococcus ureasiticus</i> were the main microbial species for biogenic amine degradation and could be isolated as the potential strains for biogenic amine degradation in fermented foods.