The anaerobic digestion of biomass is a multi-stage process involving different types of microorganisms. Biogas projects employing anaerobic digestion and aiming at waste resource utilization are now becoming the most effective and promising techniques used for the treatment of urban waste,industrial wastewater, poultry excreta, and excess sludge from wastewater plants,and so on.In the process, in addition to macronutrients such as carbon (C), nitrogen (N), phosphorus (P), and sulphur (S), trace elements play a crucial role in the growth and metabolism of anaerobic microorganisms. Trace elements such as micro-nutrients are necessary for the metabolism of anaerobic microbes and important components in the anaerobic fermentation enzyme system, which can activate the activity of enzymes in methanogenic systems. Trace elements, such as iron (Fe), cobalt (Co), nickel (Ni), and so on, could promote the growth of the methanogens known to be crucial to the activity of enzymes in methanogenic systems, and to further speed up the biosynthesis of methane. The stimulation and antagonism of trace elements plays a very significant role in the performance and stability of biogas digesters, which are operated with energy crops, animal excreta, crop residues, organic fraction of municipal solid wastes, and other types of organic waste. The deficiency or unavailability of these elements in biogas digesters is probably the first reason of poor process efficiency (fermentation system operation instability and declining gas production) without any other obvious reason, despite proper management and control of other operational and environmental parameters. This paper reviews the biological effects of trace elements, methanogens demand for trace elements and the role of trace elements in methane synthesis on one hand, and the research status at home and abroad about the influence of trace elements such as iron (Fe), cobalt (Co), nickel (Ni), and so on, on anaerobic fermentation on the other hand. Trace elements Fe, Co, and Ni can improve the efficiency of conversion of volatile fatty acids (VFA) and eliminate the phenomenon of the accumulation of VFA. They also could antagonize the inhibitory effect induced by sodium ions, ammonia nitrogen, and increase the methane yield and keep the stability of anaerobic digestion process. Through review, the effects of trace elements on anaerobic fermentation may help to maintain the operational stability of the biogas project. Further, such knowledge is indispensable for a rational dosage of these metals to ensure maximum, high solid substrate conversion rates and to prevent disturbances in reactor performance using a minimum amount of metals. Additionally, understanding the potential environmental risks due to adding trace elements is currently insufficient.% 厌氧发酵是一项多种微生物参与的处理有机废弃物的技术，目前正成为处理、利用城市垃圾、工业有机废水、畜禽粪便和污水厂剩余污泥最有效、前景最广阔的手段之一。在此过程中微生物生长不仅需要碳（C）、氮（N）、磷（P）、硫（S）等大量元素，而且需要多种微量元素。微量元素是维持厌氧微生物生长代谢和厌氧发酵酶系统活性的重要组成成分。微量元素铁（Fe）、钴（Co）、镍（Ni）等能够促进产甲烷菌的生长和激活酶的活性，进而加快甲烷的生物合成。微量元素的刺激和拮抗作用对沼气工程的稳定运行起重要作用，在其他影响厌氧发酵的因素都正常的条件下，其不足往往会是导致厌氧发酵系统运行稳定性和产气量下降的首要原因。该文一方面对微量元素在厌氧发酵系统中的生物效应，产甲烷菌对微量元素的需求，微量元素在甲烷合成途径中的作用进行了归纳；另一方面还着重对 Fe、Co、Ni 等微量元素对厌氧发酵的影响的国内外研究现状进行了总结，其不仅能够提高挥发性脂肪酸转化效率，消除挥发性脂肪酸的累积现象，提高甲烷产气量，而且能够拮抗钠离子、氨氮等的抑制作用，进一步维持厌氧发酵的稳定运行。然而高固体有机废弃物厌氧发酵过程中对微量元素的需求量的研究还不健全，而且当前外源添加微量元素潜在的环境风险也认识不足。通过综述微量元素对厌氧发酵的影响可能会对维持沼气工程的稳定运行有着一定的借鉴意义。
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