基于DNA高通量测序分析生料酿醋过程中的真菌多样性

Fungal diversity during raw vinegar brewing process as revealed by high-throughput sequencing

摘要:

[目的] 了解生料酿醋不同阶段的真菌群落结构及其变化规律，为生料酿醋工艺优化提供理论指导。[方法] 从山西一家生料酿醋企业采集原料、麸曲、发酵缸醋醅、熏醋样、淋醋样等涉及生料酿醋各阶段的样品共51份，扩增真菌ITS1区序列并利用高通量测序技术分析真菌多样性。[结果] 除5份样品未扩增成功外，在剩余46份样品中共检测到489个真菌OTU，以子囊菌为主（占88.3%）。原料、麸曲、发酵缸醋醅、熏醋样、淋醋样等不同组别间在真菌群落结构方面存在显著差异。原料和麸曲中的真菌物种丰富度最低，发酵缸醋醅的真菌物种丰富度最高，熏醋样和淋醋样中的真菌物种丰富度又有所降低。原料和麸曲中的优势真菌分别为酿酒酵母和黑曲霉，是发酵阶段真菌的重要来源，但发酵缸醋醅中也检测到大量可能来源于发酵室环境的真菌。发酵缸醋醅在不同发酵时期间也存在明显的真菌群落结构差异，并可据此划分成发酵前期（包括发酵第2-13天的样品）和发酵后期（包括发酵第17-46天的样品）。酿酒酵母和亮白曲霉的丰度在发酵前期显著高于发酵后期，而黑曲霉、一种小戴卫霉科真菌等的丰度在发酵后期显著高于发酵前期。[结论] 生料酿醋的不同阶段和发酵缸醋醅发酵的不同时期，其真菌群落结构都存在明显差异。酿酒酵母和黑曲霉是发酵阶段的优势真菌。本研究为生料酿醋工艺优化提供了理论依据。

Abstract:

[Objective] To understand the structure and dynamics of fungal community during raw vinegar brewing. [Methods] In total 51 samples including raw materials, starter, fermenting samples in urns, smoking cupei and leaching cupei were collected from a raw vinegar making enterprise in Shanxi Province, and fungal diversity was analyzed by high throughput sequencing of ITS1 regions. [Results] Except 5 samples having failure amplifications, 489 fungal OTUs were detected in the remaining 46 samples, dominated by Ascomycetes (88.3%). There were significant fungal community differences among groups. The species richness was the lowest in raw materials and starter, the highest in fermenting samples, and medium in smoking and leaching cupei. The dominant fungi from raw materials and starter were Saccharomyces cerevisiae and Aspergillus niger, respectively, which were important inocula for fermentation. There were also obvious fungal community variations during fermentation in urns, which were further divided into early (F2 to F13) and late (F17 to F46) fermentation stages. The abundance of S. cerevisiae and Aspergillus candidus was significantly higher in the early fermentation stage, whereas that of A. niger and Davidiellaceae sp. was significantly higher in the late fermentation stage. [Conclusion] There are significant fungal community variations among different brewing steps and among different fermentation stages in urns. S. cerevisiae and A. niger represent the main fungi contributing to raw vinegar fermentation. This study provides a theoretical basis for the optimization of raw vinegar brewing process.