毛木耳发酵料堆细菌群落多样性分析

The Dynamics of Bacterial Community in Fermentation Pile of Auricularia cornea

为了探究毛木耳培养料发酵过程中,微生物群落的多样性变化以及各时期标记物种,为揭示发酵机制提供依据,从而为筛选发酵过程的有益细菌提供参考。将栽培毛木耳的发酵培养料混匀建堆,自然发酵,发酵周期35d,从初始开始,每次翻堆前采用5点取样法取5个平行样本,一共5组25个样本;对样本进行16S rDNA扩增子建库及测序,并进行数据分析。结果表明:毛木耳发酵堆中的微生物多样性丰富,每个时期的OTU样本,数目分别为2807、2271、2553、2465和2106个,建堆期最多,第4次翻堆最少;PCA分析结果显示,同一时期的样本聚集,不同时期的样本分开;UPGM聚类显示,每个时期的不同重复在同一个分支内,每个时期形成独立分支。根据丰度的占比,在属水平,发酵堆中的菌群演化规律为尿素芽孢杆菌属从发酵初期到发酵完成,相对丰度依次为0.53%,18.51%,20.31%,37.10%和40.85%;嗜热共生杆菌属相对丰度依次为2.90%,4.69%,6.88%,7.22%和18.27%,占比逐渐提高;嗜热双孢菌属Thermobispora与己酸菌属Caproiciproducens在D0期的相对丰度分别为14.55%与13.42%,发酵一个月后下降为1.82%与0.08%。随着发酵的进行,微生物的α多样性呈下降趋势,局部在第二次翻堆有反弹;PCA及UPGM聚类能将各个时期发酵堆有效分开;在属水平,发酵堆的微生物群落从建堆期的嗜热双孢菌属Thermobispora与己酸菌属Caproiciproducens演变成发酵成熟期的尿素芽孢杆菌属Ureibacillus与嗜热共生杆菌Symbiobacterium。

Explore the diversity of microbial communities and marker species during the fermentation process of the Auricu-laria cornea cultures.Mix the fermented culture material to build a pile.After it was done,it would be naturally fermented.The fermentation cycle was 40 days.From the beginning,five parallel samples were taken every ten days using the 5-point sampling method,five groups of up to 25.16S rDNA amplicon libraries construction and sequencing were performed on these samples and then subject to data analysis.The experimental results showed that the fermentation pile had abundant microbe,and there were 2807,2271,2553,2465 and 2106 OTUs in each group,and the pile build-up time had the most abundant OTUs,and the fermentation terminal had the least.PCA analysis revealed that samples in the same group were located closer,while those from different groups separated.UPGM clustered samples from the same group in one clade.In the genus level,the abundance of Ureibacillus and Symbiobacterium was getting higher,with the relative one of 0.53%,18.51%,20.31%,37.10%,and 40.85%for Ureibacillus,and 2.90%,4.69%,6.88%,7.22%,and 18.27% for Symbiobacterium.However,the abundance of Thermobispora and Caproiciproducens declined during the fermentation,from 14.55%and 13.42%in the be-ginning to 1.82%and 0.08%after the fermentation was completed.Theαdiversity of the fermentation pile microbial has a downward trend with a partial rebound in the D20.PCA and UPGM data analysis can distinguish every fermentation time point.In the genus level,the fermentation pile microbes were dominant by Thermobispora and Caproiciproducens in the be-ginning,changed to Ureibacillus and Symbiobacterium in the end.