该研究将不同粉碎度的小麦分别用于高温大曲发酵，对发酵过程变化及成曲率进行监测，并运用宏基因组测序技术对发酵结束后黑、黄、白曲的微生物群落结构及功能特征进行解析。结果表明，低粉碎度组曲坯温度最快达到60 ℃，且三次升温松弛有度，不会长时间过热，成品曲中黄曲占比最高（82.37%）。高粉碎度组黑、黄曲中主要细菌累积相对丰度占比达28.95%以上，远高于其余两组。中、低粉碎度组黑、黄曲中微生物群落以曲霉菌属（Aspergillus）、罗萨氏菌属（Rasamsonia）、拟青霉菌属（Paecilomyces）、篮状菌属（Talaromyces）等真菌为主，主要真菌总占比达73.95%以上，明显高于高粉碎度组。黑曲和黄曲的大曲糖苷水解酶（Glycoside Hydrolases, GHs）基因主要由罗萨氏菌属、曲霉菌属、拟青霉菌属等散囊菌目真菌贡献（占比46.78%~62.33%），白曲中的GH基因主要源于糖多孢菌属（Saccharopolyspora）。研究结果进一步证实了小麦粉碎度对大曲品质的重要影响，并初步探究了不同碳水化合物活性酶基因的微生物来源，对全面了解高温大曲发酵、科学指导高温大曲生产有切实参考。

Wheat ground to different degrees was fermented in high-temperature Daqu (HT-Daqu) to evaluate the effects of grinding on fermentation and the maturity ratio. After fermentation, the microbial community structures and functional characteristics of three categories (black, yellow, and white) of HT-Daqu were analyzed via metagenomic sequencing. The temperature of the low-grinding-degree group reached 60 ℃ in the shortest time, with time gaps observed in three temperature rises with no prolonged overheating. Yellow Daqu accounted for 82.37% of the mature Daqu in this group, which was the highest ratio among the three groups with different grinding degrees. The total relative abundance of major bacteria in black and yellow Daqu of the high-grinding-degree group was more than 28.95%, which was higher than that in the other two groups. Aspergillus, Rasamsonia, Paecilomyces, and Talaromyces dominated the microbial community in the medium- and low-grinding-degree groups, accounting for more than 73.95% of the total, significantly higher than the highgrinding-degree group. The genes of glycoside hydrolases in black and yellow Daqu were mainly contributed by Eurotiales including Rasamsonia, Aspergillus, and Paecilomyces (46.78%~62.33%), while those in white Daqu were found to be mainly derived from Saccharopolyspora. These results demonstrate the importance of the grinding degree of wheat on the quality of Daqu and identifies the microbial sources of genes encoding different carbohydrate-active enzymes. The findings have a practical significance for understanding the fermentation of HT-Daqu comprehensively and guiding the production of HTDaqu scientifically.

四川省中央引导地方科技发展专项项目（2021ZYD0102）