School of Resources and Environment, Henan Polytechnic University
Unconventional Gas Research Institute, Henan Polytechnic University
School of Energy Resources, China University of Geosciences
Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region

强化煤制微生物甲烷的研究备受重视，是煤层气的一项有效增产措施。向发酵系统中添加导电材料可以有效促进直接种间电子传递提高甲烷产率，在强化有机物厌氧降解方面潜力巨大。以长焰煤作为底物构建厌氧发酵系统，通过对生物甲烷产气量、中间关键液相产物、微生物群落结构、产甲烷代谢路径以及发酵前后残煤表面官能团等的测试和分析，探讨了石墨烯对厌氧发酵产生物甲烷的促进效应。结果表明，在以煤为底物的厌氧发酵系统中添加0.4 g/L的石墨烯有效增强了整个厌氧发酵的进行，不仅提高了甲烷产气量，同时也提前了甲烷的产出高峰期。在发酵初期，水解菌群(Paraclostridium)和产氢产乙酸菌群(Alcaligenes、Sphaerochaeta)的活性增强，前期积累了充足的营养物质。在产甲烷高峰期，添加石墨烯后Methanoculleus丰度降低而Methanosarcina丰度显著提高，乙酰辅酶A脱羰基酶/合成酶β亚基和γδ亚基作为乙酸合成途径中的关键酶，分别增加了233.54%和3.32%，这使得Methanosarcina丰度明显上升且主要进行乙酸营养型产甲烷，细菌群落中能够利用乙酸乙醇类物质的Geobacter和Anaerovorax丰度增高，其中丰度升高较明显的Geobacter可能通过与石墨烯辅助的生物电连接与Methanosarcina进行DIET，这种电子传递方式在一定程度上加速了生物甲烷的生成。产气残煤表面的羰基碳(C=O)、羧基碳(COO—)在添加石墨烯后分别下降了42.8%和49.5%，说明石墨烯有效促进了微生物对煤的降解。石墨烯的添加提高了菌群的活性和降解效率，加快了厌氧发酵进程，为产甲烷菌群提供了丰富的底物，提高了甲烷产气量。

The research of enhancing biomethanation of coal has been paid much attention, which is an effective measure for increasing coalbed methane production. Adding conductive material to the digestive system can effectively accelerate direct interspecific electron transfer and increase methane production, which has great potential in enhancing the anaerobic digestion of organic matter. In this study, long-flame coal was used as the substrate to construct an anaerobic digestion system. The effect of the addition of graphene on biomethane production was discussed from the aspects of cumulative methane yield, the changes of key intermediates in the liquid phase, the microbial community structure, the methane metabolic pathway, and the changes of surface functional groups in residual coal after anaerobic digestion. The results showed that adding 0.4 g/L of graphene to the anaerobic digestion system based on coal effectively enhanced the entire anaerobic digestion process, not only enhanced methane production, but also brought forward the peak of methane production. At the early stage of digestion, the activities of hydrolytic bacteria (Paraclostridium) and hydrogen-production and aceogenic microflora (Alcaligenes and Sphaerochaeta) were enhanced, and sufficient nutrients were accumulated in the early stage. At the peak of methane production, the abundance of Methanoculleus decreased while the abundance of Methanosarcina significantly increased after the addition of graphene. The β subunit and γδ subunit of acetyl-coa decarbonyase/synthase, as key enzymes in the acetic acid synthesis pathway, increased by 233.54% and 3.32%, respectively. This significantly increased the abundance of Methanosarcina and mainly produced methane in the form of acetic acid nutrition. The abundance of Geobacter and Anaerovorax bacteria that can use ethyl acetate increased, and the Geobacter with high abundance were likely to DIET with Methanosarcina by bioelectric connection assisted by graphene. This electron transport mode accelerated the formation of biomethane to some extent. The carbonyl carbon (C=O) and carboxyl carbon (COO—) on the surface of residual coal decreased by 42.8% and 49.5%, respectively, after the addition of graphene, indicating that graphene effectively promoted the degradation of coal by microflora. The addition of graphene improves the activity and degradation efficiency of microflora, speeds up the process of anaerobic digestion, provides abundant substrate for methanogenic microflora, and improves methane production.

国家自然科学基金重点资助项目(42230804)；国家自然科学基金面上资助项目(42072193)

周艺璇，苏现波，赵伟仲，等. 煤微生物甲烷化的石墨烯强化机制[J]. 煤炭学报，2023，48(11)：4145−4156.

ZHOU Yixuan，SU Xianbo，ZHAO Weizhong，et al. Enhancement of bioconversion of coal to methane by graphene[J]. Journal of China Coal Society，2023，48(11)：4145−4156.