Spatiotemporal distribution of environmental microbiota in spontaneous fermentation workshop: The case of Chinese Baijiu

The strong-flavor Baijiu (SFB) brewing workshop is a complex ecosystem with diverse microbiomes. As a potential source of microbiomes in fermentation, microbiota in the environmental microecology may affect the quality and flavor of SFB. Here, we report the collection of environmental microecological samples from three SFB workshops with different usage times (named 70a, 30a, and new, respectively). We used 16S rRNA and internal transcribed spacer (ITS) gene amplicon full-length sequencing to explore the microbial community structure in SFB. The SourceTracker tool was used to investigate links among fermentation samples, raw materials, and the environment and decipher the construction process in the workshop indoor environment. Lactobacillus acetotolerans was the most important bacterial genus in Zaopei after fermentation, whereas other types of samples exhibited different prokaryotic community structures. The composition of the fungal community was similar, with Saccharomycopsis fibuligera, Debaryomyces hansenii, Lichtheimia ramosa, Lichtheimia corymbifera, and Pichia kudriavzevii being the most abundant, and were detected in most samples. Further comparison of the microbiota in the workshop environment showed that the diversity of the microbiota in the indoor environment decreased, showing different clustering patterns under the influence of location. With increasing usage time, the contribution of deterministic processes to the assembly of the prokaryotic community increases, and the community structure tends to stabilize, exhibiting its own characteristics. SFB-fermenting resident functional fungi were the major components of the fungal community, and SourceTracker analysis also highlighted the contributions of Zaopei, Daqu, and tool surfaces as fungal sources. This study is the first to comprehensively monitor the microbial profile of the SFB production environment. This research can be extended to involve more complex spontaneous fermentation environment microbiota and has important implications for the control of spontaneous fermentation.