Abstract:[Objective] This study aims to investigate the effects of aeration on the microbial community structure and metabolic functional genes in pickles.[Method] Amplicon sequencing was carried out for the 16S rRNA and ITS rRNA gene fragments from three groups (aerated group, sealed group, and the initial group) within the same pickle system. The EasyAmplicon pipeline and PICRUSt2 were employed to assess bacterial and fungal community diversity, composition, and functional gene variations.[Result] Compared with the initial group, the sealed group showed only minor changes in microbial diversity, whereas the aerated group exhibited significant microbial divergence from the initial group. After aeration, the number of rare taxa sharply declined, and the relative abundance of a few dominant genera (such as Lactobacillus in bacteria and Rhodotorula and Wickerhamomyces in fungi) increased substantially. In terms of functional genes, the bacteria displayed decreased relative abundance of functional genes related to amino acid metabolism, cell motility, and quorum sensing but increased relative abundance of functional genes associated with lipid metabolism, replication, and repair. Notably, the relative abundance of functional genes linked to nitrite metabolism also showed a marked increase. Additionally, among fungal functional genes associated with growth morphology, the relative abundance of saprotrophs and yeasts significantly increased. And oxygen-related energy metabolism and stress defense functional genes (such as octanoyl-acyl carrier protein biosynthesis, fatty acid β-oxidation and D-myoinositol-1 metabolism) also exhibited elevated relative abundance in fungi.[Conclusion] The significant changes in microbial community structure and metabolic functions after aeration may lead to nitrite accumulation and spoilage. Therefore, the occurrence of aeration should be minimized, and the quality of pickles can be controlled by regulating environmental factors and the microbial community in pickles.
