Identification, detection, and spatial resolution of Clostridium populations responsible for cellulose degradation in a methanogenic landfill leachate bioreactor
Identification, detection, and spatial resolution of Clostridium populations responsible for cellulose degradation in a methanogenic landfill leachate bioreactor
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DOI：
10.1128/aem.70.4.2414-2419.2004
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发表时间：
2004-04-01
影响因子：
4.4
通讯作者：
Blackall, LL
中科院分区：
文献类型：
--
作者：
Burrell, PC;O'Sullivan, C;Blackall, LL
在厌氧垃圾渗滤液生物反应器中加入结晶纤维素和无菌垃圾渗滤液，直至达到稳定状态。测定了纤维素水解、产酸和产甲烷的情况。附着在纤维素表面的微生物被假设为纤维素水解菌。16S rRNA基因克隆文库是由这个附着部分和混合部分（与纤维素颗粒相关的生物量和浮游阶段）制备的。两个克隆文库均以厚壁菌门序列为主（附着文库占100%，混合文库占90%），大多数属于梭状芽胞杆菌的5个谱系之一。克隆组1（与粪状梭菌亲缘关系最密切）、克隆组2（与热梭菌亲缘关系最密切）和克隆组5（与纤维素溶剂拟杆菌亲缘关系最密切）包含梭菌群III中的序列。克隆组3序列属于Clostridium group XIVa（与Clostridium sp.菌株XB90亲缘关系最密切）。克隆组4序列隶属于一个深分支的梭状芽孢杆菌谱系，其外围与梭状芽孢杆菌群VI相关。该单系群包括一个新的梭状芽孢杆菌簇，命名为VIa簇。设计并合成了这5个基团的特异性荧光原位杂交（FISH）探针，实验结果表明，克隆基团1、2、4和5的探针靶向细菌在纤维素颗粒表面非常丰富，可能是垃圾填埋场生物反应器中关键的纤维素降解微生物。针对克隆组3的FISH探针瞄准了浮游期的细胞，这些生物被假设为葡萄糖发酵剂。
An anaerobic landfill leachate bioreactor was operated with crystalline cellulose and sterile landfill leacbate until a steady state was reached. Cellulose hydrolysis, acidogenesis, and methanogenesis were measured. Microorganisms attached to the cellulose surfaces were hypothesized to be the cellulose hydrolyzers. 16S rRNA gene clone libraries were prepared from this attached fraction and also from the mixed fraction (biomass associated with cellulose particles and in the planktonic phase). Both clone libraries were dominated by Firmicutes phylum sequences (100% of the attached library and 90% of the mixed library), and the majority fell into one of five lineages of the clostridia. Clone group 1 (most closely related to Clostridium stercorarium), clone group 2 (most closely related to Clostridium thermocellum), and clone group 5 (most closely related to Bacteroides cellulosolvens) comprised sequences in Clostridium group III. Clone group 3 sequences were in Clostridium group XIVa (most closely related to Clostridium sp. strain XB90). Clone group 4 sequences were affiliated with a deeply branching clostridial lineage peripherally associated with Clostridium group VI. This monophyletic group comprises a new Clostridium cluster, designated cluster VIa. Specific fluorescence in situ hybridization (FISH) probes for the five groups were designed and synthesized, and it was demonstrated in FISH experiments that bacteria targeted by the probes for clone groups 1, 2, 4, and 5 were very abundant on the surfaces of the cellulose particles and likely the key cellulolytic microorganisms in the landfill bioreactor. The FISH probe for clone group 3 targeted cells in the planktonic phase, and these organisms were hypothesized to be glucose fermenters.