Discovery of a novel Lactiplantibacillus phage enhancing flavor compound production in high-temperature Daqu.

Bacteriophages (phages) are an understudied yet pivotal component of fermentation ecosystems, with potential implications for product quality through phage-host interplay. However, the functional roles of phage communities or individual phages in Daqu (saccharifying and fermenting agent for Baijiu) remain largely unexplored. This study utilized virome analysis to investigate the composition and functional dynamics of the phage community during high-temperature Daqu (HTD) incubation. We identified Inoviridae as the dominant phage family, with most phages belonging to the Caudoviricetes class. These phages exhibited a broad host range, targeting genera such as Cronobacter, Escherichia, and Lactiplantibacillus. Notably, all phages infecting lactic acid bacteria were predicted to belong to the class Caudoviricetes. Using a culture-dependent approach, we isolated a novel phage, Lactiplantibacillus plantarum phage ZMDQ02, which features a long non-contractile tail and an icosahedral head, characteristic of the Caudoviricetes class. Whole-genome analysis confirmed its taxonomic novelty. Simulated Daqu fermentation experiments revealed that ZMDQ02 positively influences Daqu flavor development. HS-SPME-GC-MS-based flavor profiling showed that ZMDQ02 markedly promoted the biosynthesis of tetramethylpyrazine and furfural, two key compounds responsible for baking and sauce-like aromas, thereby contributing to the formation of the distinctive HTD flavor profile. These findings provide the first functional evidence that phages critically contribute to the flavor properties of Daqu, establishing a new dimension in understanding the role of phages in fermented food ecosystems.