Diversity and dynamic succession of microorganisms during Daqu preparation for Luzhou- flavour liquor using second-generation sequencing technology

The dominant microorganisms in Daqu were analysed using high-throughput sequencing during fermentation. There were 16 dominant fungal species accounting for 90.8% of the total fungal abundance with Pichia kudriavzevii accounting for 43%. There were 18 dominant bacterial species accounting for 94% of the total bacterial abundance with Lactobacillus representing >50%. The succession pattern of the microbial populations showed that, prior to the top temperature, the microbial population was rich, consisting of Pichia (yeast), Aspergillus, Rhizopus (moulds), Weissella, Pediococcus and Lactobacillus (bacteria). During the top temperature phase, Thermoascus aurantiacus predominated. After this, in the final Daqu, the microflora were mainly yeasts (Pichia, Saccharomycetales) and the bacteria Lactobacillus, Bacillus, Weissella and Pediococcus. These results lay the foundation for further studies on functional microorganisms in the preparation and the mechanism of Daqu formation.