Analysis of Bacterial Diversity in Different Types of Daqu and Fermented Grains From Danquan Distillery

Abstract

Bacterial communities in high-temperature Daqu and fermented grains are important for brewing Jiang-flavor Baijiu such as Danquan Baijiu. Daqu is a saccharifying and fermenting agent, which has a significant impact on the flavor of Baijiu. However, bacterial communities in three different types of samples from the Danquan distillery (dqjq_ck, dqjqcp, and dqjp3) were still unclear, which limited further development of Danquan Baijiu. “dqjq_ck” and “dqjqcp” indicate high-temperature Daqu at days 45 and 135, respectively. “dqjp3” indicates fermented grains. In this study, the bacterial communities of three samples were analyzed by Illumina Miseq high-throughput sequencing. The bacterial communities of three samples primarily composed of thermophilic bacteria and bacteria with stress resistance. The most abundant species in dqjq_ck, dqjqcp, and dqjp3 were Comamonas, Bacillus, and unclassified Lactobacillales, respectively. The main bacteria included Bacillus, Comamonas, Myroides, Paenibacillus, Acetobacter, Kroppenstedtia, Staphylococcus, Saccharopolyspora, Planifilum, Lactobacillus, Acinetobacter, Oceanobacillus, Enterococcus, Thermoactinomyces, Lactococcus, Streptomyces, Saccharomonospora, Tepidimicrobium, Anaerosalibacter, unclassified_Lactobacillales, unclassified_Thermoactinomycetaceae_1, unclassified_Bacillaceae_2, unclassified_Bacillales, unclassified_Microbacteriaceae, unclassified_Rhodobacteraceae, unclassified_Actinopolysporineae, and unclassified_Flavobacteriaceae in three samples (percentage was more than 1% in one of three samples). In our study, the succession of microbiota in three samples representing three important stages of Danquan Baijiu brewing was revealed. This article lays a good foundation for understanding the fermentation mechanism and screening some excellent indigenous bacteria to improve the quality of Danquan Baijiu in future.

Characterizing the Contribution of Functional Microbiota Cultures in Pit Mud to the Metabolite Profiles of Fermented Grains

“…In Daqu , as well as two types of PM cultures, 13 genera of AT bacteria were identified, including Thermoactinomyces , Limosilactobacillus , Kroppenstedtia , Weissella , etc., which dominated in DQ, while Bacillus and Aneurinibacillus shared in both MC and FC, and Lysinibacillus also dominated in the latter ( Figure 3 A). Kroppenstedtia , known for its high amylase and lipase secretion and organic acid metabolism [ 38 ], along with Bacillus , was highlighted as a functional bacteria in Daqu [ 39 ]. Aneurinibacillus , notable for its cellulose degradation of various enzymes, such as alkyl or aryl transferases, methyl transferases, and secretion abilities, was first detected in PM cultures, contributing to the formation of methyl esters [ 40 ].…”

Optimizing the Conditions of Pretreatment and Enzymatic Hydrolysis of Sugarcane Bagasse for Bioethanol Production

“… 57 Our previous study also found that with the higher HTD-making temperature, most yeasts and molds were destroyed, and the microbial community of HTD primarily propagated thermophilic bacteria such as Bacillus . 58 In addition, Bacillus was the dominant bacterium in sample “dqjqcp”. 58 Therefore, we suggested that Bacillus was primarily responsible for producing ethanol rather than yeast in the Danquan Baijiu production.…”

“… 58 In addition, Bacillus was the dominant bacterium in sample “dqjqcp”. 58 Therefore, we suggested that Bacillus was primarily responsible for producing ethanol rather than yeast in the Danquan Baijiu production. Therefore, we isolated the bacterial strain Bacillus sp.…”

“…Ethanol-producing bacteria include Bacillus , Zymomonas mobiliz, Leuconostoc , and Thermoanaerobacterales. , Our previous study showed that the dominant fungi included Aspergillus, Zygosaccharomyces, Issatchenkia, Monascus, Millerozyma, Thermoascus, Thermomyces, Hyphopichia, Rhizomucor, Lichtheimia , and Cladosporium in three samples from Danquan Baijiu production (HTD samples “dqjq_ck” and “dqjqcp”, and the fermented grain sample dqjp3) . Our previous study also found that with the higher HTD-making temperature, most yeasts and molds were destroyed, and the microbial community of HTD primarily propagated thermophilic bacteria such as Bacillus . In addition, Bacillus was the dominant bacterium in sample “dqjqcp” .…”