Contrasting bacterial community structure in artificial pit mud-starter cultures of different qualities: a complex biological mixture for Chinese strong-flavor Baijiu production

Abstract

The complex starter culture for artificial pit mud (APMSC) hosts a wide variety of microbial communities that play a crucial role in Chinese strong-flavor Baijiu production. Based on its organoleptic properties, the quality of APMSC can be divided into normal and inferior quality grades. However, the relationship between the APMSC microbial community and APMSC quality is poorly understood. In this study, the bacterial community structure in normal and inferior APMSC derived from two different production batches was analyzed using denaturing gradient gel electrophoresis and Illumina MiSeq sequencing. Highly similar patterns of bacterial diversity and community structure were observed in the APMSC samples of the same quality, and a significant higher bacterial species diversity (Shannon index and Chao1) was detected in the normal compared to the inferior APMSC samples. Fifteen genera were detected in the APMSC samples, and seven (Caproiciproducens, Clostridium, Lactobacillus, Bacillus, Pediococcus, Rummeliibacillus, and Sporolactobacillus) were dominant, accounting for 92.12-99.89% of total abundance. Furthermore, the bacterial communities in the normal and inferior APMSC had significantly different structure and function. The normal APMSC was characterized by abundant Caproiciproducens and Clostridium and high caproic and butyric acid contents. In contrast, the inferior APMSC was overrepresented by Lactobacillus and Bacillus and lactic and acetic acids. This study may help clarify the key microbes sustaining APMSC ecosystem stability and functionality, and guide future improvements in APMSC production.

Structural and Functional Changes in Prokaryotic Communities in Artificial Pit Mud during Chinese Baijiu Production

“…Finally, the mixture was covered with polyester film and incubated at ambient temperature (20 to 34°C, with an average of 24°C) for 34 days (from 28 July 2017 to 30 August 2017). The starter culture preparation is described in detail in our previous study (45).…”

Analysis of bacterial communities in pit mud from Zhijiang Baijiu distillery using denaturing gradient gel electrophoresis and high- throughput sequencing

“…Therefore, the large number of C. kluyveri and increased share of Clostridium cluster IV might lead to the increased levels of ethyl caproate in Baijiu from an aged cellar. The content of ethyl caproate was reported to be positively correlated with Chinese strong flavour Baijiu quality (28). Thirdly, since Petrimonas (5), Sedimentibacte (5) and Syntrophomonas (32) produce acetic acid, the reduced share of Petrimonas, Sedimentibacter, and Syntrophomonas may result in decreased acetic acid and ethyl acetate from the aged cellar, while both compounds may increase in Baijiu from the young cellar (33).…”

“…In agreement with previous work , the results using the two methods (DDGE and high‐throughput sequencing) are mutually supportive. Comparison of the results indicated that the microorganisms detected by DGGE were recovered by high‐throughput sequencing with exception of Anaerolineaceae and Planctomycete.…”

“…Comparison of the results indicated that the microorganisms detected by DGGE were recovered by high‐throughput sequencing with exception of Anaerolineaceae and Planctomycete. This difference between the two methods may reflect the use of different primers .…”

Detection of Viable and Total Bacterial Community in the Pit Mud of Chinese Strong-Flavor Liquor Using Propidium Monoazide Combined With Quantitative PCR and 16S rRNA Gene Sequencing

“…Previous studies reported that Caproiciproducens could produce caproic acid (Kim et al, 2015), and that Clostridium sensu stricto, as one kind of strictly anaerobic bacteria, was regarded as the true Clostridium (Chai et al, 2019). It could ferment cellulosic-based biomass and sugar to form butyric acid and eventually to produce ethyl caproate (Barker et al, 1945;Liu et al, 2019). Excessive levels of ethyl lactate might make the liquor harmony worse, while ethyl caproate is recognized as a key component favorably influencing the flavor of CSFL (Tao et al, 2014).…”