对以纤维素为唯一碳源条件下瘤胃细菌群落动态变化的研究

The Research of Dynamic Changes of Rumen Bacteria Community Cultured in the Medium with Cellulose as the Sole Carbon Source

本试验使用以纤维素为唯一碳源的培养基培养瘤胃细菌,然后利用宏基因组技术分析瘤胃细菌群落在不同时间点的动态变化。将瘤胃微生物菌液接种到由厌氧稀释液和纤维素配制的纤维素选择性培养基中,连续培养50 h,分别在10、20、30、40和50 h取样,提取DNA,进行16S rRNA基因测序,分析细菌群落多样性和丰度变化。结果显示,不同时间点α多样性指数Ace差异显著(P<0.05),其中30 hα多样性显著高于40、50 h(P<0.05);β多样性指数分析显示,40和50 h的菌群组成与10和20 h的菌群组成差异显著(P<0.05),30 h是细菌群落演替的时间点;已知的纤维降解菌属如丁酸弧菌属(Butyrivibrio)、假丁酸弧菌属(Pseudobutyrivibrio)、梭菌属(Clostridium)的丰度均呈逐渐增加的趋势。纤维杆菌属(Fibrobacter)在不同时间点的丰度没有差异(P>0.05)。在培养过程中发现,潜在的纤维降解菌Acholeplasma,Alkaliphilus,Blautia,GW_34的丰度随培养时间增加逐渐增加,并均在50 h丰度显著高于10 h(P<0.05)。根据微生物菌群的多样性、丰富度、已知纤维降解菌和其他潜在纤维降解菌的丰度变化,确定30~40 h为下一步富集分离纤维降解菌的参考时间段,该结果为下一步稀释培养分离新的纯纤维降解菌提供了理论依据。

In this experiment,the medium with cellulose as the sole carbon source was used as the growth environment of the rumen bacterial community,and then the 16S rRNA sequence technique was used to analyze the dynamic changes of the rumen bacterial community at different time points.The rumen bacteria were incubated in the media made of anaerobic dilution solution with cellulose for 50 h,and samples were collected at 10,20,30,40 and 50 h,respectively.The DNA samples were extracted and analyzed by 16S rRNA sequencing.The results showed that the Ace of bacteria community was significant different among different time points(P<0.05),and that at 30 h was significantly higher than that of 40 and 50 h(P<0.05).The beta diversity proved that the bacteria community at 40 and 50 h was significant different with that at 10 and 20 h(P<0.05),the bacteria community succession happened in 30 h.The typed rumen cellulolytic bacteria,like Butyrivibrio,Pseudobutyrivibrio,Clostridium,increased with time increasing,but the abundance of Fibrobacter was not significantly changed(P>0.05).With time passing by,the abundances of Acholeplasma,Alkaliphilus,Blautia,GW_34 were increasing and significantly higher at 50 h compared with 10 h(P<0.05)during culture period.In summary,the reference time of enrichment and separation of cellulytic bacteria was 30 to 40 h,and the results provided a theoretical basis for further dilution culture and isolation of new pure cellulytic bacteria.