纤维素降解混合培养物的16S rRNA基因序列分析

Analysis of 16S rRNA gene sequences of a cellulolytic mix-culture enrichment

以牦牛瘤胃内容物为接种物,以滤纸为唯一碳源富集到一个降解纤维素的混合培养物.构建混合培养物的16S rRNA基因文库,共获得49个序列,分为7个OTU.其中19个序列与已培养细菌的16S rRNA基因相似性>97%,占总序列的38.8%;2个古菌的序列与甲烷菌的16S rRNA基因相似性分别为99%和98%,占总序列的4.1%;28个序列属于未培养细菌,占总序列的57.1%.未培养的序列形成4个独立的系统发育分支,其中3个未培养分支与在其他环境中的黏附在纤维素上的瘤胃细菌的16S rRNA基因序列相似性>97%,推测这3类微生物可能与纤维素降解相关.

By using filter paper as the sole carbon source, we obtained a cellulose-degrading mix- culture enrichment with yak rumen content as the inoculant. The 16S rRNA gene library was constructed and a total of 49 clones were obtained and they were clustered as seven operational taxonomy units （OTUs） at the similarity level of 97% sequence similarity. 19 sequences were related to Actinomyces ruminicola and Lactobacillus vitulinus, accounting for 38.8% of the total clones. 2 sequences were related to Methanobrevibacter olleyae and M. ruminantium, accounting for 4.1% of the total clones. The remaining 28 clones were affiliated to the uncultured groups, accounting for 57.1% of the total clones. Based on the phylogenetic analysis, three uncultured OTUs were related to the rumen bacteria attached to celluiose at 〉97% 16S rRNA similarities. They were supposed to be responsible for cellulose degradation in rumen