Daqu and environmental microbiota regulate fatty acid biosynthesis via driving the core microbiota in soy sauce aroma type liquor fermentation

Fatty acids are considered as important compounds for the aroma and taste of Chinese liquor. Revealing the core microbiota related with fatty acid biosynthesis and how they are influenced are essential to control fatty acids in spontaneous Chinese liquor fermentation. Herein, we identified the core microbiota related with fatty acid biosynthesis based on their microbial abundance, abundance and expression level of genes related with fatty acid biosynthesis, using high-throughput amplicon sequencing, metagenomic and metatranscriptomic analysis, respectively. Acetilactobacillus, Kroppenstedtia, Saccharomyces, Paecilomyces and Pichia were identified as the core microbiota (the criteria for identifying core microbiota: average relative abundance ≥1 %, average abundance of related genes >400 fragments per kilobase of transcript per million fragments mapped [FPKM], and expression level of related genes >1000 FPKM) related with fatty acid biosynthesis. SourceTracker analysis showed that Daqu mainly provided Kroppenstedtia (34.01 %) and Acetilactobacillus (3.31 %). Ground mainly provided Pichia (47.47 %), Saccharomyces (16.17 %) and Paecilomyces (8.55 %). Structural equation model revealed that Daqu and environmental microbiota drove the core microbiota (P < 0.05), and the core microbiota drove the biosynthesis of fatty acids (P < 0.05). This work revealed the important role of Daqu and environmental microbiota in fatty acid biosynthesis in liquor fermentation. It would benefit controlling fatty acids in liquor fermentation, and improving the liquor quality.