T-RFLP和454焦磷酸测序方法分析制麦过程细菌群落的动态变化

Bacterial Community Dynamics during Malting Based on T-RFLP and 454 Pyrosequencing Profiles

确定微生物菌群特性是制麦管理与优化的关键一步。本研究以两个不同收获年份及两个同批次不同制麦方式的大麦为样品,采用两种非培养计数方法,即16S核糖体RNA(16S rRNA)末端限制片段长度多态性(T-RFLP)和454焦磷酸测序,检测制麦过程细菌及乳酸菌菌群结构,以期全面、准确分析细菌群落结构及动态变化。研究结果显示:不同收获年份的大麦细菌菌群结构存在差异,整个细菌群落结构随着制麦过程而发生变化,而不同发芽方式之间并没有明显的区别。454焦磷酸测序结果显示乳酸菌有139个运算分类单元(OTU),所有样品有88%的序列覆盖了5个OTU(如Weissella、Lactobacillus和Leuconostoc菌属),说明制麦过程乳酸菌的多样性较低,优势乳酸菌相对数量随着制麦条件变化而波动,并且大麦的收获年份和制麦环境也影响乳酸菌的菌群结构。

Characterization of the microflora during malting is an essential step towards process management and optimization. The aim of this study was to characterize the bacterial communities using two culture-independent methods,including Terminal Restriction Fragment Length Polymorphism(T-RFLP) and 454 pyrosequencing,targeting the 16S rRNA gene. In order to analyze bacterial communities and dynamics fully and precisely,the same batch of barley originated from two harvest years using two malting methods was studied in entire bacterial community and lactic acid bacteria(LAB). The results showed that the bacterial community structure of barley from different years was different and changed during the malting process,but there was no significance difference between the two malting methods. Zooming in the LAB community using 454 pyrosequencing revealed a total of 139 operational taxonomic units(OTUs). LAB diversity appeared relatively limited since 88% of the sequences were covered by the same five OTUs(representing members of Weissella,Lactobacillus and Leuconostoc) present in all samples investigated. Fluctuations in the relative abundances of the dominant LAB were observed with the process conditions. In addition,both the year of harvest and malting environment influenced the LAB community structure.