泸型酒窖泥中梭菌的分离及代谢产物分析

目的] 分离窖泥中的梭菌微生物并对其代谢产物进行评估。方法] 对窖泥中梭菌群落的16S rRNA基因进行高通量测序；利用高丰度的梭菌OTU序列在KOMODO数据库进行培养基的预测，定向分离窖泥中梭菌菌株；采用顶空固相微萃取结合气相色谱质谱联用仪对窖泥和代表性梭菌菌株的挥发性代谢产物进行检测。结果] 利用KOMODO数据库预测的梭菌培养基共计筛选到31株梭菌微生物，分属于梭菌属的14个种；根据风味代谢特性，这些菌株主要分为两大类，一是C.carboxidivorans、C.sporogenes和C.tyrobutyricum等产酸为主的梭菌，二是C.beijerinckii、C.butyricum和C.sphenoides等产醇为主的梭菌。结论] 利用测序序列预测培养基有助于从窖泥中分离获得丰富的梭菌菌株，其物种和代谢能力的多样性对解析白酒复杂风味形成机理奠定了一定的基础。

Isolation and metabolic characters of Clostridium strains from pit mud of Luzhou-flavor baijiu

Objective] This study aims to isolate Clostridium strains from Luzhou-flavor baijiu pit mud and evaluate their metabolic characteristics. Methods] 16S rRNA gene sequencing was used to analyze the clostridial community structure in pit mud; specific media were predicted according to the sequences of high-abundance OTUs scattered in Clostridia using KOMODO database; volatile compounds of pit mud and the representative isolated Clostridium strains'' fermentation broth were detected by headspace solid phase microextraction combined with gas chromatography-mass spectrometry. Results] Thirty-one strains belonging to 14 species of genus Clostridium were isolated using the 7 media predicted by KOMODO database. Based on the analysis of volatile metabolites, these Clostridium strains could be divided into two clusters, including cluster I, i.e. strains mainly producing acids (C. carboxidivorans, C. sporogenes and C. tyrobutyricum) and cluster II, i.e. strains mainly producing alcohols (C. beijerinckii, C. butyricum and C. sphenoides). Conclusion] KOMODO method is helpful for the isolation of Clostridium or other bacteria from the pit mud of Luzhou-flavor baijiu, and elucidating their metabolic profiles could be conductive to analyze the function of brewing microbes in baijiu flavor formation.