高温大曲与稻草微生物群落结构及差异代谢物研究

Microbial Community Structure and Differential Metabolites of High-temperature Daqu and Rice Straw

摘要:

【目的】解析高温大曲发酵过程中不同环节稻草和高温大曲的微生物群落演替规律、差异代谢物与优势微生物的关系，初步预测高温大曲微生物的来源与贡献度。【方法】采用高通量测序技术联合液相色谱-质谱联用（LC-MS）技术分析高温大曲发酵过程中微生物群落及代谢物的变化规律。【结果】新草（XC）中优势细菌属以Pantoea和Pseudomonas为主，优势真菌属以Mrakia和Nigrospora为主；母草（MC）中优势细菌属以Bacillus和Saccharopolyspora为主。发酵各环节稻草的优势真菌属均以Thermomyces和Aspergillus为主，优势细菌属以Saccharopolyspora、Acinetobacter、Bacillus、Thermoactinomyces为主。LEfSe差异物种判别分析结果表明，高温大曲和稻草的优势细菌不存在差异显著的物种，真菌共检出6种差异物种，Alfaria和Myriococcum是稻草中的代表性真菌，Pichia、Saccharomyces、Monascus和Kodamaea是高温大曲中的代表性真菌。同时，基于Source Tracker溯源分析可知，不同环节稻草对高温大曲的细菌贡献度极低，而对高温大曲的真菌贡献度存在差异，其中，二次翻曲稻草（EFC）对拆曲大曲（CQQ）的真菌贡献度最高。通过对代谢物进行分析，稻草和高温大曲间共筛选出197种差异代谢物，且差异代谢物与优势微生物之间的关联关系构成了发酵过程的基本生物学调控机制。【结论】该研究为后续高温大曲发酵机理研究及提高传统发酵过程的可控性奠定了基础。

Abstract:

[Objective] This study was designed to elucidate the microbial community succession dynamics of rice straw and high-temperature Daqu at distinct stages of fermentation, investigate the associations between differential metabolites and dominant microorganisms, and preliminarily predict the sources and contribution of microorganisms in high-temperature Daqu. [Method] High-throughput sequencing combined with liquid chromatography-mass spectrometry (LC-MS) was used to analyze the variation patterns of microbial communities and metabolites during the fermentation of high-temperature Daqu. [Result] Pantoea and Pseudomonas were the dominant bacterial genera, while the dominant fungal genera were Mrakia and Nigrospora in new rice straw (XC). For mother rice straw (MC), Bacillus and Saccharopolyspora were identified as the dominant bacterial genera. At various fermentation stages, the dominant fungal genera were Thermomyces and Aspergillus, whereas the dominant bacterial genera were Saccharopolyspora, Acinetobacter, Bacillus, and Thermoactinomyces. LEfSe revealed no significant differences in the dominant bacterial taxa between high-temperature Daqu and rice straw. In contrast, a total of six differential fungal taxa were collectively identified through co-analysis. Among them, Alfaria and Myriococcum were recognized as the marker fungal specific to rice straw, while Pichia、Saccharomyces、Monascus, and Kodamaea were the representative marker fungal in high-temperature Daqu. Source Tracker-based source tracking analysis indicated that the bacterial contribution of rice straw to high-temperature Daqu was negligible across different stages, whereas the fungal contribution varied among stages. Notably, the second-turn rice straw (EFC) exerted the highest fungal contribution to the detached Daqu (CQQ). Metabolomic profiling revealed 197 differential metabolites between rice straw and high-temperature Daqu. The correlation network between these differential metabolites and dominant microorganisms underpinned the fundamental biological regulatory mechanisms governing the fermentation process. [Conclusion] This study establishes a foundation for subsequent investigations into the fermentation mechanism of high-temperature Daqu and for enhancing the controllability of traditional fermentation processes.