Klocke Michael, Nettmann Edith, Bergmann Ingo, Mundt Kerstin, Souidi Khadidja, Mumme Jan, Linke Bernd
Leibniz-Institut für Agrartechnik Potsdam-Bornim e.V ATB, Abteilung Bioverfahrenstechnik, Max-Eyth-Allee 100, Potsdam-Bornim, Germany.
Syst Appl Microbiol. 2008 Aug;31(3):190-205. doi: 10.1016/j.syapm.2008.02.003. Epub 2008 May 22.
The two-phase leach-bed system is a biogas reactor system optimized for the utilization of energy crop silages at maximized loading rates under maintenance of an optimal microbial activity. In this study, a characterization of the methanogenic microbial community within this reactor system was conducted for the first time. Accordingly, effluent samples from the anaerobic filter and the silage digesting leach-bed reactors of both a laboratory-scale two-phase biogas reactor system and a scaled-up commercial on-farm pilot plant were investigated. In total, five Archaea-specific 16S rDNA libraries were constructed and analyzed by amplified rDNA restriction analysis (ARDRA), with subsequent phylogenetic analysis of nucleotide sequences for individual ARDRA patterns. A quantification of major methanogenic Archaea groups was conducted by real-time PCR. A total of 663 clones were analyzed and 45 operational taxonomic units (OTUs) related to methanogenic Archaea were detected. These OTUs were related to the orders Methanosarcinales, Methanomicrobiales and Methanobacteriales, as well as the hitherto uncultured CA-11 and ARC-I groups, and most of them occurred throughout all the compartments of both two-phase biogas reactors. The proportion of acetotrophic to hydrogenotrophic methanogens differed between the laboratory and the pilot scale system. A total of 56% of the clones from the 16S rDNA library derived from the laboratory biogas system were assigned to presumably acetotrophic members of Methanosarcinales. In contrast, these OTUs were less abundant in the 16S rDNA library derived from samples of the pilot plant. Therein, the most dominant OTUs were Methanoculleus-related OTUs, which presumably indicated the predominant presence of hydrogenotrophic methanogens. These findings were confirmed by group-specific quantitative real-time PCR assays. The results indicated that the fraction of acetotrophic and hydrogenotrophic methanogens within a biogas reactor caused certain variations, which may reflect varying substrate utilization during methanogenesis.
两相浸出床系统是一种沼气反应器系统，该系统经过优化，可在维持最佳微生物活性的情况下，以最大负荷率利用能源作物青贮饲料。在本研究中，首次对该反应器系统内产甲烷微生物群落进行了表征。因此，对实验室规模的两相沼气反应器系统和扩大规模的商业化农场中试装置的厌氧过滤器以及青贮消化浸出床反应器的出水样本进行了研究。总共构建了五个古菌特异性16S rDNA文库，并通过扩增rDNA限制性分析（ARDRA）进行分析，随后对各个ARDRA模式的核苷酸序列进行系统发育分析。通过实时PCR对主要产甲烷古菌群体进行定量分析。共分析了663个克隆，检测到45个与产甲烷古菌相关的操作分类单元（OTU）。这些OTU与甲烷八叠球菌目、甲烷微菌目和甲烷杆菌目以及迄今未培养的CA-11和ARC-I组有关，并且它们中的大多数出现在两个两相沼气反应器的所有隔室中。实验室规模系统和中试规模系统中，乙酸营养型产甲烷菌与氢营养型产甲烷菌的比例有所不同。来自实验室沼气系统的16S rDNA文库中，共有56%的克隆被归类为可能属于甲烷八叠球菌目的乙酸营养型成员。相比之下，这些OTU在来自中试装置样本的16S rDNA文库中丰度较低。其中，最主要的OTU是与甲烷袋状菌相关的OTU，这可能表明氢营养型产甲烷菌占主导地位。这些发现通过组特异性定量实时PCR分析得到了证实。结果表明，沼气反应器内乙酸营养型和氢营养型产甲烷菌的比例存在一定差异，这可能反映了产甲烷过程中底物利用情况的不同。
