Dynamic Changes in Microbiome and Metabolome during Sun-Drying of Oysters (Crassostrea gigas), a Traditional Procedure in South China

Sun-drying constitutes a traditional method employed in the preparation of dried oysters within the coastal regions of South China. However, its ramifications on nutritional attributes and the genesis of flavor-contributory compounds in the resultant dried oysters remain significantly unexplored. This research endeavors to scrutinize the repercussions of the production process on the microbiota and metabolites within dried oysters. Utilizing 16s rRNA amplicon sequencing, the identification of 409 operational taxonomic units (OTUs) ensued, wherein Proteobacteria, Bacteroidetes, Firmicutes, Tenericutes, and Actinobacteria surfaced as the primary pathogenic bacteria present in oyster samples. Analysis of the dried oyster sample metabolomes via LC-MS unveiled a discernible augmentation in compounds associated with steroid hormone biosynthesis, arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, and linoleic acid metabolism throughout the entirety of the drying process. Subsequent exploration into the association between metabolites and bacterial communities highlighted the prevailing coexistence of Mycoplasma, Psychrilyobacter, and Vibrio demonstrating negative correlations with a substantial number of metabolites across categories including organic acid and its derivatives, nucleotide and its metabolites, free fatty acids, and amino acids. Conversely, Shewanella and Arcobacter exhibited positive correlations with these metabolite categories. This exhaustive investigation offers invaluable insights into the dynamic alterations within the microbiota and metabolites of dried oysters across diverse drying periods. These findings are anticipated to significantly contribute to the advancement of production techniques and the formulation of enhanced safety measures for the processing of dried oysters.