Characterization of microbial community and yeast functional traits in Apocynum venetum honey from Xinjiang

Apocynum venetum honey, a nutrient-rich product of natural fermentation, exhibits antimicrobial properties due to its low water activity and high sugar content. This study utilized four groups of Xinjiang A. venetum honey, with three biological replicates per group for amplicon sequencing and three technical replicates via gradient dilution for yeast isolation to isolate yeasts using various culture-dependent methods and to analyze microbial diversity and composition through culture-independent techniques. Yeast strains were identified using 26S rDNA sequencing, and their characteristics such as growth, production of ester, ethanol, and H₂S, as well as tolerance levels (ethanol, pH, glucose, SO₂), were compared to the commercial brewer's yeast Saccharomyces cerevisiae EC-1118. The culture-independent analysis revealed significant variations in bacterial richness and fungal diversity among different habitats. No bacterial or fungal species were found to be shared across the habitats with distinct group-specific compositions observed at phylum, class, and genus levels. The culture-dependent methods led to the isolation of 337 strains, of which 33 were yeasts belonging to four main species, representing 22.85% of the total isolates. Among these, EC-1118 demonstrated superior ethanol production and tolerance, while specific strains exhibited notable ester, H₂S and sugar fermentation capabilities. This integrated approach provides valuable insights into yeast characteristics and microbial community structure in A. venetum honey, offering a basis for targeted strain selection, fermentation optimization, and efficient utilization of microbial resource in the food industry.