University of Innsbruck, Institute of Microbiology, Technikerstr. 25, A-6020 Innsbruck, Austria.
Waste Manag. 2011 Mar;31(3):431-7. doi: 10.1016/j.wasman.2010.10.020. Epub 2010 Nov 10.
Since biogas production is becoming increasingly important the understanding of anaerobic digestion processes is fundamental. However, large-scale digesters often lack online sensor equipment to monitor key parameters. Furthermore the possibility to selectively change fermenting parameter settings in order to investigate methane output or microbial changes is limited. In the present study we examined the possibility to investigate the microbial community of a large scale (750,000 L) digester within a laboratory small-scale approach. We studied the short-term response of the downscaled communities on various fatty acids and its effects on gas production and compared it with data from the original digester sludge. Even high loads of formic acid led to distinct methane formation, whereas high concentrations of other acids (acetic, butyric, propionic acid) caused a marked inhibition of methanogenesis coupled with an increase in hydrogen concentration. Molecular microbial techniques (DGGE/quantitative real-time-PCR) were used to monitor the microbial community changes which were related to data from GC and HPLC analysis. DGGE band patterns showed that the same microorganisms which were already dominant in the original digester re-established again in the lab-scale experiment. Very few microorganisms dominated the whole fermenting process and species diversity was not easily influenced by moderate varying fatty acid amendments--Methanoculleus thermophilus being the most abundant species throughout the variants. MCR-copy number determined via quantitative real-time-PCR--turned out to be a reliable parameter for quantification of methanogens, even in a very complex matrix like fermenter sludge. Generally the downscaled batch approach was shown to be appropriate to investigate microbial communities from large-scale digesters.
随着沼气生产变得越来越重要，对厌氧消化过程的理解是基础。然而，大型消化器通常缺乏在线传感器设备来监测关键参数。此外，为了研究甲烷产量或微生物变化而有选择地改变发酵参数设置的可能性也受到限制。在本研究中，我们研究了在实验室小规模方法中研究大型（750,000 升）消化器中微生物群落的可能性。我们研究了小规模群落对各种脂肪酸的短期响应及其对气体产生的影响，并将其与原始消化器污泥的数据进行了比较。即使甲酸的高负荷也会导致明显的甲烷形成，而其他酸（乙酸、丁酸、丙酸）的高浓度会导致产甲烷作用明显抑制，同时氢气浓度增加。分子微生物技术（DGGE/定量实时 PCR）用于监测微生物群落变化，这些变化与 GC 和 HPLC 分析的数据相关。DGGE 带型表明，在原始消化器中已经占优势的相同微生物再次在实验室规模实验中重新建立。很少有微生物主导整个发酵过程，并且物种多样性不易受到适度变化的脂肪酸添加的影响-整个变体中最丰富的物种是 Methanoculleus thermophilus。通过定量实时 PCR 确定的 MCR 拷贝数-即使在像发酵器污泥这样非常复杂的基质中，也被证明是定量甲烷菌的可靠参数。一般来说，缩小批量方法被证明适合研究大型消化器中的微生物群落。
