A database of absorption and fluorescence spectra, including molar absorption coefficients and fluorescence quantum yields, has been compiled for 125 photochemically relevant compounds. An accompanying program enables calculation of oscillator strengths, natural radiative lifetimes, transition dipole moments, Forster energy‐transfer rates, multicomponent analysis, simulations of fluorescence spectra upon energy transfer among linear arrays of pigments, calculations of blackbody radiator curves at different temperatures and Lorentzian and Gaussian peak distributions. The program runs under Windows 95 and is equipped with extensive literature references and help features.

Fermentation pit mud, an important reservoir of diverse anaerobic microorganisms, is essential for Chinese strong-aroma liquor production. Pit mud quality, according to its sensory characteristics, can be divided into three grades: degraded, normal, and high quality. However, the relationship between pit mud microbial community and pit mud quality is poorly understood, as are microbial associations within the pit mud ecosystem. Here, microbial communities at these grades were compared using Illumina MiSeq sequencing of the variable region V4 of the 16S rRNA gene. Our results revealed that the pit mud microbial community was correlated with its quality and environmental factors. Species richness, biodiversity, and relative and/or absolute abundances of Clostridia, Clostridium kluyveri, Bacteroidia, and Methanobacteria significantly increased, with corresponding increases in levels of pH, NH 4 ؉ , and available phosphorus, from degraded to high-quality pit muds, while levels of Lactobacillus, dissolved organic carbon, and lactate significantly decreased, with normal samples in between. Furthermore, 271 pairs of significant and robust correlations (cooccurrence and negative) were identified from 76 genera using network analysis. Thirteen hubs of cooccurrence patterns, mainly under the Clostridia, Bacteroidia, Methanobacteria, and Methanomicrobia, may play important roles in pit mud ecosystem stability, which may be destroyed with rapidly increased levels of lactic acid bacteria (Lactobacillus, Pediococcus, and Streptococcus). This study may help clarify the relationships among microbial community, environmental conditions, and pit mud quality, allow the improvement of pit mud quality by using bioaugmentation and controlling environmental factors, and shed more light on the ecological rules guiding community assembly in pit mud. Chinese strong-aroma liquor (CSAL), a traditional alcoholic beverage, accounts for Ͼ70% of both national liquor industry production (12 billion liters) and sales volume ($80 billion) (1, 2). Its production is a typical recycling process using solid-state fermentation. In brief, fermented grains obtained from the last fermentation round are mixed with crushed raw materials (sorghum, wheat, corn, rice, and sticky rice) for distillation to give CSAL (3). After cooling, the steamed mixture is supplied with a 10 to 20% (wt/wt) Daqu starter. Next, the above-mentioned mixture is placed into a fermentation vessel (underground cuboid soil pit, 2 m wide by 3 m long by 2 m deep), sealed, and anaerobically fermented for about 60 days at 28 to 32°C (2). The inside walls of the pit are covered with fermentation pit mud (FPM), which is prepared initially by incubating the mixture of clay, spent grain, bean cake powder, and fermentation bacteria (e.g., Clostridium spp.) (2). After fermentation, the fermented grains taken out of the pit are distilled to give liquor after new raw materials are supplied, and then the mixture is applied to the next round of fermentation, as described above. It is widely believe...

Many microorganisms in the environment participate in the fermentation process of Chinese liquor. However, it is unknown to what extent the environmental microbiota influences fermentation. In this study, high-throughput sequencing combined with multiphasic metabolite target analysis was applied to study the microbial succession and metabolism changes during Chinese liquor fermentation from two environments (old and new workshops). SourceTracker was applied to evaluate the contribution of environmental microbiota to fermentation. Results showed that Daqu contributed 9.10 to 27.39% of bacterial communities and 61.06 to 80.00% of fungal communities to fermentation, whereas environments (outdoor ground, indoor ground, tools, and other unknown environments) contributed 62.61 to 90.90% of bacterial communities and 20.00 to 38.94% of fungal communities to fermentation. In the old workshop, six bacterial genera ( Lactobacillus [11.73% average relative abundance], Bacillus [20.78%], Pseudomonas [6.13%], Kroppenstedtia [10.99%], Weissella [16.64%], and Pantoea [3.40%]) and five fungal genera ( Pichia [55.10%], Candida [1.47%], Aspergillus [10.66%], Saccharomycopsis [22.11%], and Wickerhamomyces [3.35%]) were abundant at the beginning of fermentation. However, in the new workshop, the change of environmental microbiota decreased the abundances of Bacillus (5.74%), Weissella (6.64%), Pichia (33.91%), Aspergillus (7.08%), and Wickerhamomyces (0.12%), and increased the abundances of Pseudomonas (17.04%), Kroppenstedtia (13.31%), Pantoea (11.41%), Acinetobacter (3.02%), Candida (16.47%), and Kazachstania (1.31%). Meanwhile, in the new workshop, the changes of microbial community resulted in the increase of acetic acid, lactic acid, malic acid, and ethyl acetate, and the decrease of ethyl lactate during fermentation. This study showed that the environmental microbiota was an important source of fermentation microbiota and could drive both microbial succession and metabolic profiles during liquor fermentation. IMPORTANCE Traditional solid-state fermentation of foods and beverages is mainly carried out by complex microbial communities from raw materials, starters, and the processing environments. However, it is still unclear how the environmental microbiota influences the quality of fermented foods and beverages, especially for Chinese liquors. In this study, we utilized high-throughput sequencing, microbial source tracking, and multiphasic metabolite target analysis to analyze the origins of microbiota and the metabolic profiles during liquor fermentation. This study contributes to a deeper understanding of the role of environmental microbiota during fermentation.