Yang Sheng-Bing, Lu Zhen-Ming, Shen Han-Jun, Fu Jun-Jie, Yang Yang, Zhang Xiao-Juan, Chai Li-Juan, Wang Song-Tao, Zhang Su-Yi, Shen Cai-Hong, Shi Jin-Song, Xu Zheng-Hong
Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China; National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, PR China.
Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China; National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, PR China; National Engineering Research Center of Solid-State Brewing, Luzhou 646000, PR China.
Int J Food Microbiol. 2025 Nov 2;442:111392. doi: 10.1016/j.ijfoodmicro.2025.111392. Epub 2025 Aug 15.
Solid-state fermentation heterogeneity causes microenvironmental differences, shaping diverse microbial communities and metabolite compositions. Here, we aimed to investigate the variations in Qu-aroma between the inner (I-) and outer (O-) layers of medium-temperature Daqu (MT-Daqu) starter, and to analyze the differences in microbial communities as well as the associated metabolic pathways related to Qu-aroma volatile organic compounds (VOCs). Firstly, quantitative descriptive analysis revealed that the I-layer exhibited intensified rancid-roasted notes, whereas the O-layer showed stronger grain and woody notes. Secondly, a total of 225 VOCs were identified from 88 inner and outer layer samples using HS-SPME-GC-MS, among which 43 differential VOCs were confirmed between the layers (VIP > 1, P < 0.05, and Fold change ≥1.5 or ≤0.67). Thin film (TF)-SPME-GC-O/MS revealed 52 and 47 odors with corresponding VOCs in the I- and O-layers, respectively. Subsequently, cross-referencing metagenomic and metabolic databases revealed that 37 aroma-active VOCs were functionally linked to six metabolic modules within the MT-Daqu microbial metabolic network. Finally, integrated metagenomic and amplicon sequencing identified potential functional microorganisms associated with specific metabolic modules. Five genera, including Kroppenstedtia and Thermomyces, were identified as characteristic of the I-layer, while 22 genera, such as Lactobacillus and Saccharomycopsis, were characteristic of the O-layer. Notably, Kroppenstedtia, Thermomyces, Lactobacillus, Saccharomycopsis, and Weissella were ubiquitously associated with all six metabolic modules across both layers of MT-Daqu. This study delivers a perspective for clarifying the spatial heterogeneity of Qu-aroma and its microbial drivers.
固态发酵异质性导致微环境差异，塑造了多样的微生物群落和代谢物组成。在此，我们旨在研究中温大曲（MT-大曲）酒醅内层（I-层）和外层（O-层）之间曲香的差异，并分析微生物群落的差异以及与曲香挥发性有机化合物（VOCs）相关的代谢途径。首先，定量描述分析表明，I-层呈现出更强烈的酸败烤香气味，而O-层则表现出更强的谷物和木香气味。其次，使用顶空固相微萃取-气相色谱-质谱联用（HS-SPME-GC-MS）从88个内层和外层样品中总共鉴定出225种VOCs，其中两层之间确认了43种差异VOCs（VIP>1，P<0.05，且倍数变化≥1.5或≤0.67）。薄膜（TF）-SPME-GC-O/MS分别在I-层和O-层中揭示了52种和47种带有相应VOCs的气味。随后，交叉引用宏基因组和代谢数据库表明，37种具有香气活性的VOCs在功能上与MT-大曲微生物代谢网络中的六个代谢模块相关联。最后，综合宏基因组和扩增子测序确定了与特定代谢模块相关的潜在功能微生物。包括克氏菌属和嗜热霉菌属在内的五个属被鉴定为I-层的特征属，而包括乳酸杆菌属和类酵母属在内的22个属是O-层的特征属。值得注意的是，克氏菌属、嗜热霉菌属、乳酸杆菌属、类酵母属和魏斯氏菌属在MT-大曲的两层中均与所有六个代谢模块普遍相关。本研究为阐明曲香的空间异质性及其微生物驱动因素提供了一个视角。
