Aims Microorganisms in fermentation pits (FPs) play key roles for Chinese‐strong‐aromatic‐liquor (CSAL) production. However, the microbial community in the FPs is still poorly understood. Here, the aim of this study was to reveal the diversity and potential functions of microbiota in FPs. Methods and Results Sequencing‐by‐synthesis‐based metagenomic sequencing and annotation results revealed that the microbiota of FPs was primarily composed of Firmicutes (54·6%), Euryarchaeota (15·3%), Bacteroidetes (10·1%), Gammaproteobacteria (5·8%), Opisthokonta (5·7%) and Unclassified_Bacteria (2·3%). And 133 genera were identified as the dominant genera of this fermentative food. Lactobacillus, Sedimentibacter, Syntrophomonas, Methanoculleus, Methanobacterium, Bacillus, Clostridium, Galactomyces, Candida, Pichia, Penicillium and Aspergillus were defined as active populations for biosynthesizing the characteristic volatile compounds of CSAL. The study also revealed that the microbial community structures changed significantly with different cellar ages and over different geographical regions. (i) The presence of Bacteroidetes was the most distinctive feature that characterized the different FPs ages. (ii) Distinct contents of Gammaproteobacteria and Euryarchaeota were observed at different positions in the FPs. (iii) Euryarchaeota markedly contributed to the generation of the character of the liquors with distinct geographical associations. Conclusions This study demonstrated that the changes of microbial communities determined the different quality characteristics of CSAL. Significance and Impact of the Study This research contributes to a deeper understanding of the FPs microbial composition and shows a new microbial resource for biotechnological applications.

To guide therapeutic strategies and to monitor the state changes in the disease, a low-cost, portable, and easily fabricated microfluidic-chip-integrated three-dimensional (3D) microchamber was designed for capturing and analyzing breast cancer cells. Optimally, a colorimetric sensor array was integrated into a microfluidic chip to discriminate the metabolites of the cells. The ultraviolet polymerization characteristic of poly(ethylene glycol) diacrylate (PEGDA) hydrogel was utilized to rapidly fabricate a three-layer hydrogel microfluidic chip with the designed structure under noninvasive 365 nm laser irradiation. 2-Hydroxyethyl methacrylate (HEMA) was added to the prepolymer in order to increase the adhesive capacity of the microchip’s surface for capturing cells. 1-Vinyl-2-pyrrolidone (NVP) was designed to improve the toughness and reduce the swelling capacity of the hydrogel composite. A non-toxic 3D hydrogel microarray chip (60 mm × 20 mm × 3 mm) with low immunogenicity and high hydrophilicity was created to simulate the real physiological microenvironment of breast tissue. The crisscross channels were designed to ensure homogeneous seeding density. This hydrogel material displayed excellent biocompatibility and tunable physical properties compared with traditional microfluidic chip materials and can be directly processed to obtain the most desirable microstructure. The feasibility of using a PEGDA hydrogel microfluidic chip for the real-time online detection of breast cancer cells’ metabolism was confirmed using a specifically designed colorimetric sensor array with 16 kinds of porphyrin, porphyrin derivatives, and indicator dyes. The results of the principal component analysis (PCA), the hierarchical cluster analysis (HCA), and the linear discriminant analysis (LDA) suggest that the metabolic liquids of different breast cells can be easily distinguished with the developed PEGDA hydrogel microfluidic chip. The PEGDA hydrogel microfluidic chip has potential practicable applicability in distinguishing normal and cancerous breast cells.

The complex microbiota of pit mud of solid-state fermentation reactors used for the production of Chinese liquor is responsible for producing one of the oldest distillates in the world. We apply a deep-sequencing approach to characterize the microbiota from pits that have been in use for up to 440 years.

This study investigated aroma changes in Hui Li red Sichuan pepper across five different harvesting times within their typical optimum period based on 24 traditional solar terms, employing sensory evaluation, electronic nose (E-nose), gas chromatography-ion mobility spectrometry (GC-IMS) combined with relative odour activity value (ROAV) and partial least squares discriminant analysis (PLS-DA). Sensory analysis indicated that peppers were characterised by green, citrus, minty, sweet, woody, and peppery numbing aroma attributes. E-nose revealed the greatest aroma difference in peppers occurred between the early and late optimum harvest stages. GC-IMS identified 71 volatile compounds, with esters being the most abundant. Six key compounds identified were crucial for distinguishing peppers harvested at different times. Findings provided a valuable contribution to decide the optimal harvest window for Hui Li red Sichuan peppers, maximising their applications in the seasoning industry.

Traditional Chinese strong-aroma baijiu (CSAB) fermentation technology has been used for thousands of years. Microbial communities that are enriched in continuous and uninterrupted fermentation pits (FPs) are important for fermentation. However, changes in the metabolic functional genes in microbial communities of FPs are still under-characterized. High-throughput sequencing technology was applied to comprehensively analyze the diversity, function, and dynamics of the metabolic genes among FPs of different ages, positions, and geographical regions. Approximately 1,375,660 microbial genes derived from 259 Gb metagenomic sequences of FPs were assembled and characterized to understand the impact of FP microorganisms on the quality of CSAB and to assess their genetic potential. The core functional gene catalog of FPs, consisting of 3379 ubiquitously known gene clusters, was established using Venn analysis. The functional profile confirmed that the flavor compounds in CSAB mainly originate from the metabolism of carbohydrates and amino acids. Approximately 17 key gene clusters that determine the yield and quality of CSAB were identified. The potential mechanism was associated with the biosynthesis of host compounds in CSAB, which relies on the abundance of species, such as Lactobacillus, Clostridium, Saccharomycetales, and the abundance of functional genes, such as CoA dehydrogenase, CoA transferase, and NAD dehydrogenase. Furthermore, the detailed metabolic pathways for the production of main flavor compounds of CSAB were revealed. This study provides a theoretical reference for a deeper understanding of substance metabolism during CSAB brewing and may help guide the future exploration of novel gene resources for biotechnological applications.