关键词: 羊肉香肠；宏基因组；微生物多样性；生物胺代谢

Abstract: The changes in biogenic amine contents of naturally fermented mutton sausage samples during different fermentation stages were detected by high performance liquid chromatography (HPLC), and the microbial community succession was explored using metagenomics. Meanwhile, the correlation between biogenic amines and microbial diversity was established, and the abundance and functional annotation of microorganisms and enzymes were investigated by means of the Non-Redundant (NR) Protein Sequence database, evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The results showed that biogenic amine contents increased first and then decreased with fermentation time, and the content of spermine was the highest among eight tested biogenic amines. A total of 43 phyla, 60 classes, 112 orders, 201 families, 465 genera and 2 156 species of microorganisms were identified in fermented mutton sausage samples. Staphylococcus, Vibrio, Oenococcus and Haemophilus were the dominant bacteria. Spearman correlation analysis showed that the contents of tryptamine, cadaverine, tyramine, spermidine, and spermine were significantly (P < 0.05) related to some of the top 30 most abundant bacterial genera, while the contents of histamine, putrescine, and phenylethylamine were not. After analyzing the metagenomic data using the KEGG database, biogenic amine metabolic pathways and related enzymes and bacteria were found, including those that could metabolize cadaverine, putrescine, spermidine and spermine, those that could catabolize tryptamine, phenylethylamine and tyramine, but not those that could metabolize histamine. Apart from the correlation between biogenic amines and microbial flora, this study also clarified the relationship of biogenic amine metabolism with enzymes and microorganisms.

Key words: fermented mutton sausage; metagenome; microbial diversity; biogenic amine metabolism