The roles of acetotrophic and hydrogenotrophic methanogens during anaerobic conversion of biomass to methane: a review
The roles of acetotrophic and hydrogenotrophic methanogens during anaerobic conversion of biomass to methane: a review
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DOI：
10.1007/s11157-008-9131-1
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发表时间：
2008-06-01
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影响因子：
--
通讯作者：
Scherer, Paul
中科院分区：
文献类型：
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作者：
Demirel, Burak;Scherer, Paul
在各种生物质转化工艺中，生物厌氧消化是利用各种生物质基质生产沼气最经济的方法之一。除了聚合物的水解之外，产甲烷细菌的活性和性能在产甲烷过程中是至关重要的。本文的目的主要是回顾最近的文献中关于发生在颗粒生物质厌氧转化为甲烷（不是废水处理）的过程中的产乙酸和产氢产甲烷菌，而这篇综述不包括乙酸氧化细菌的活性。产氢和产乙酸甲烷菌都是甲烷生成的最后一步所必需的，但是关于它们在这一过程中的作用的报道非常有限。尽管如此，仍然可以得出一些结论。在低浓度的乙酸盐下，通常丝状的Methanosaeta物种占主导地位，例如，通常在污水污泥中观察到。显然，高浓度的有毒离子剂，如氨、硫化氢（H2S）和挥发性脂肪酸（VFA），优选抑制甲烷八叠球菌科，特别是允许由不规则细胞团块组成的甲烷八叠球菌属物种的生长，例如，在牛粪里嗜热条件可以有利于棒状或球状的氢营养产甲烷菌。还观察到嗜热甲烷八叠球菌，但没有嗜热甲烷八叠球菌。其他环境因素可能有利于氢营养细菌，例如，在生物质反应器中停留时间短或低。然而，目前还没有关于工艺参数的一般规则，这有利于氢营养型产甲烷菌。据推测，它仅取决于氢浓度，这在文献中通常没有提及。
Among different conversion processes for biomass, biological anaerobic digestion is one of the most economic ways to produce biogas from various biomass substrates. In addition to hydrolysis of polymeric substances, the activity and performance of the methanogenic bacteria is of paramount importance during methanogenesis. The aim of this paper is primarily to review the recent literature about the occurrence of both acetotrophic and hydrogenotrophic methanogens during anaerobic conversion of particulate biomass to methane (not wastewater treatment), while this review does not cover the activity of the acetate oxidizing bacteria. Both acetotrophic and hydrogenotrophic methanogens are essential for the last step of methanogenesis, but the reports about their roles during this phase of the process are very limited. Despite, some conclusions can still be drawn. At low concentrations of acetate, normally filamentous Methanosaeta species dominate, e.g., often observed in sewage sludge. Apparently, high concentrations of toxic ionic agents, like ammonia, hydrogen sulfide (H2S) and volatile fatty acids (VFA), inhibit preferably Methanosaetaceae and especially allow the growth of Methanosarcina species consisting of irregular cell clumps, e.g., in cattle manure. Thermophilic conditions can favour rod like or coccoid hydrogenotrophic methanogens. Thermophilic Methanosarcina species were also observed, but not thermophilic Methanosaetae. Other environmental factors could favour hydrogentrophic bacteria, e.g., short or low retention times in a biomass reactor. However, no general rules regarding process parameters could be derivated at the moment, which favours hydrogenotrophic methanogens. Presumably, it depends only on the hydrogen concentration, which is generally not mentioned in the literature.