Clostridium aromativorans sp. nov., isolated from pit mud used for producing Wuliangye baijiu

A strictly anaerobic, gram-positive bacterium, designated as WLY-B-L2^T, was isolated from pit mud of a fermentation pit located at Wuliangye 501# baijiu workshop in Yibin (Sichuan province, PR China). The strain was strictly anaerobic, Gram-positive with straight or somewhat rod shaped cells which were 0.5-0.7 μm wide and 1.7-3.1 μm long, arranged singly or in pairs. The strain can utilize D-galacturonic acid, methyl pyruvate, L-lactamine, L-alanyl - L-glutamine, L-alanyl - L-histidine, glycerol, pyruvate, L-alanyl - L-threonine, L-methionine, L-phenylalanine, L-valine + L-aspartic acid, L-serine, L-valine, and thymidine as carbon sources. Major cellular fatty acids are C_{16: 0} (24.6%), anteiso-C_{15: 0} (16.5%), and iso-C_{15: 0} (14.1%). Based on 16S rRNA gene sequence, WLY-B-L2^T is most closely related to Clostridium luticellarii FW431^T; they exhibit 97.42% 16S rRNA similarity. Additionally, the digital DNA-DNA hybridization (dDDH) value between them is 28.10%. WLY-B-L2^T has a G + C content of 34.16 mol%. Based on the evidence presented here, WLY-B-L2^T (CICC 25133^T = JCM 35127^T) is proposed as the type strain of a novel species, designated as Clostridium aromativorans sp. nov, that could produce butyric acid and volatile flavor components, such as ethyl valerate, ethyl acetate and 2-pentanone.

Tandem Solid-Phase Extraction Columns for Simultaneous Aroma Extraction and Fractionation of Wuliangye and Other Baijiu

Wuliangye baijiu is one of the most famous baijiu in China, with a rich, harmonic aroma profile highly appreciated by consumers. Thousands of volatiles have been identified for the unique aroma profile. Among them, fatty acid esters have been identified as the main contributors to the aroma profile. In addition, many non-ester minor compounds, many of which are more polar than the esters, have been identified to contribute to the characteristic aroma unique to Wuliangye baijiu. The analysis of these minor compounds has been challenging due to the dominance of esters in the sample. Thus, it is desirable to fractionate the aroma extract into subgroups based on functional group or polarity to simplify the analysis. This study attempts a new approach to achieve simultaneous volatile extraction and fractionation using tandem LiChrolut EN and silica gel solid-phase extraction (SPE) columns. A baijiu sample (10 mL, diluted in 40 mL of water) was first passed through the LiChrolut EN (1.0 g) column. The loaded LiChrolut EN column was then dried with air and coupled with a silica gel (5.0 g) SPE column with anhydrous Na₂SO₄ (10.0 g) in between. The volatile compounds were eluted from the LiChrolut EN column and simultaneously fractionated on the silica gel column based on polarity. The simultaneous extraction and fractionation technique enabled the fractionations of all fatty acid esters into less polar fractions. Fatty acids, alcohols, pyrazines, furans, phenols, hydroxy esters, and other polar compounds were collected in more polar fractions. This technique was used to study the volatile compounds in Wuliangye, Moutai, and Fengjiu baijiu. In addition to fatty acid esters, many minor polar compounds, including 2,6-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-3,5-dimethylpyrazine, p-cresol, and 2-acetylpyrrole, were unequivocally identified in the samples. The procedure is fast and straightforward, with low solvent consumption.

Wuliangye strong aroma baijiu promotes intestinal homeostasis by improving gut microbiota and regulating intestinal stem cell proliferation and differentiation

BACKGROUND

Wuliangye strong aroma baijiu (hereafter, Wuliangye baijiu) is a traditional Chinese grain liquor containing short-chain fatty acids, ethyl caproate, ethyl lactate, other trace components, and a large proportion of ethanol. The effects of Wuliangye baijiu on intestinal stem cells and intestinal epithelial development have not been elucidated. Here, the role of Wuliangye baijiu in intestinal epithelial regeneration and gut microbiota modulation was investigated by administering a Lieber-DeCarli chronic ethanol liquid diet in a mouse model to mimic long-term (8 weeks') light/moderate alcohol consumption (1.6 g kg-1 day-1) in healthy human adults.

RESULTS

Wuliangye baijiu promoted colonic crypt proliferation in mice. According to immunofluorescence and reverse transcription-quantitative polymerase chain reaction analyses, compared with the ethanol-only treatment, Wuliangye baijiu increased the number of intestinal stem cells and goblet cells and the expression of enteroendocrine cell differentiation markers in the mouse colon. Furthermore, gut microbiota analysis showed an increase in the relative abundance of microbiota related to intestinal homeostasis following Wuliangye baijiu administration. Notably, increased abundance of Bacteroidota, Faecalibaculum, Lachnospiraceae, and Blautia may play an essential role in promoting stem-cell-mediated intestinal epithelial development and maintaining intestinal homeostasis.

CONCLUSIONS

In summary, these findings suggest that Wuliangye baijiu can be used to regulate intestinal stem cell proliferation and differentiation in mice and to alter gut microbiota distributions, thereby promoting intestinal homeostasis. This research elucidates the mechanism by which Wuliangye baijiu promotes intestinal health. © 2024 Society of Chemical Industry.