Popp Denny, Schrader Steffi, Kleinsteuber Sabine, Harms Hauke, Sträuber Heike
Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, 04318 Leipzig, Germany.
Department of Analytical Chemistry, UFZ - Helmholtz Centre for Environmental Research, 04318, Leipzig, Germany.
FEMS Microbiol Ecol. 2015 Sep;91(9):fiv103. doi: 10.1093/femsec/fiv103. Epub 2015 Aug 30.
Plants like sweet clover (Melilotus spp.) are not suitable as fodder for cattle because of harmful effects of the plant secondary metabolite coumarin. As an alternative usage, the applicability of coumarin-rich plants as substrates for biogas production was investigated. When coumarin was added to continuous fermentation processes codigesting grass silage and cow manure, it caused a strong inhibition noticeable as decrease of biogas production by 19% and increase of metabolite concentrations to an organic acids/alkalinity ratio higher than 0.3(gorganic acids) gCaCO3 (-1). Microbial communities of methanogenic archaea were dominated by the genera Methanosarcina (77%) and Methanoculleus (11%). This community composition was not influenced by coumarin addition. The bacterial community analysis unraveled a divergence caused by coumarin addition correlating with the anaerobic degradation of coumarin and the recovery of the biogas process. As a consequence, biogas production resumed similar to the coumarin-free control with a biogas yield of 0.34 LN g(volatile solids) (-1) and at initial metabolite concentrations (∼ 0.2 g(organic acids) gCaCO3 (-1)). Coumarin acts as inhibitor and as substrate during anaerobic digestion. Hence, coumarin-rich plants might be suitable for biogas production, but should only be used after adaptation of the microbial community to coumarin.
像草木犀（Melilotus spp.）这样的植物由于其植物次生代谢产物香豆素的有害影响，不适合作为牛的饲料。作为一种替代用途，研究了富含香豆素的植物作为沼气生产底物的适用性。当香豆素添加到同时消化青贮草和牛粪的连续发酵过程中时，它会引起强烈的抑制作用，表现为沼气产量下降19%，代谢物浓度增加，导致有机酸/碱度比高于0.3（g有机酸）gCaCO3（-1）。产甲烷古菌的微生物群落以甲烷八叠球菌属（77%）和甲烷袋状菌属（11%）为主。这种群落组成不受添加香豆素的影响。细菌群落分析揭示了添加香豆素导致的差异，这与香豆素的厌氧降解和沼气过程的恢复相关。结果，沼气产量恢复到与无香豆素对照相似的水平，沼气产量为0.34 LN g（挥发性固体）（-1），初始代谢物浓度约为0.2 g（有机酸）gCaCO3（-1）。香豆素在厌氧消化过程中既作为抑制剂又作为底物。因此，富含香豆素的植物可能适合用于沼气生产，但只有在微生物群落适应香豆素后才能使用。
