State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing, 101408, China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing, 101408, China.
Chemosphere. 2020 Jul;250:126259. doi: 10.1016/j.chemosphere.2020.126259. Epub 2020 Feb 18.
In this study, single-chamber bioelectrochemical reactors (EMNS) were used to investigate the methane oxidation driven by sulfate and nitrite reduction with the auxiliary voltage. Results showed that the methane oxidation was simultaneously driven by sulfate and nitrite reduction, with more methane being converted using the auxiliary voltage. When the voltage was 1.6 V, the maximum removal rate was achieved at 8.05 mg L d. Carbon dioxide and methanol were the main products of methane oxidation. Simultaneously, nitrogen, nitrous oxide, sulfur ions, and hydrogen sulfide were detected as products of sulfate and nitrite reduction. Microbial populations were analyzed by qPCR and high-throughput sequencing. The detected methanotrophs included Methylocaldum sp., Methylocystis sp., Methylobacter sp. and M. oxyfera. The highest abundance of M. oxyfera was (3.97 ± 0.32) × 10 copies L in the EMNS-1.6. The dominant nitrite-reducing bacteria were Ignavibacterium sp., Hyphomicrobium sp., Alicycliphilus sp., and Anammox bacteria. Desulfovibrio sp., Desulfosporosinus sp. and Thiobacillus sp. were related to the sulfur cycle. Ignavibacterium sp., Thiobacillus sp. and Desulfovibrio sp. may transfer electrons with electrodes using humic acids as the electronic shuttle. The possible pathways included (1) Methane was mainly oxidized to carbon dioxide and dissolved organic matters by methanotrophs utilizing the oxygen produced by the disproportionation in the cells of M. oxyfera. (2) Nitrite was reduced to nitrogen by heterotrophic denitrifying bacteria with dissolved organic compounds. (3) Desulfovibrio sp. and Desulfosporosinus sp. reduced sulfate to sulfur ions. Thiobacillus sp. oxidized sulfur ions to sulfur or sulfate using nitrite as the electron acceptor.
在这项研究中，使用单室生物电化学反应器（EMNS）在辅助电压下研究了由硫酸盐和亚硝酸盐还原驱动的甲烷氧化。结果表明，甲烷氧化同时受到硫酸盐和亚硝酸盐还原的驱动，并且在使用辅助电压时可以转化更多的甲烷。当电压为 1.6 V 时，达到了 8.05 mg L d 的最大去除率。二氧化碳和甲醇是甲烷氧化的主要产物。同时，检测到氮气、氧化亚氮、硫离子和硫化氢作为硫酸盐和亚硝酸盐还原的产物。通过 qPCR 和高通量测序分析微生物种群。检测到的甲烷营养菌包括 Methylocaldum sp.、Methylocystis sp.、Methylobacter sp. 和 M. oxyfera。在 EMNS-1.6 中，M. oxyfera 的丰度最高为（3.97±0.32）×10 拷贝 L。优势亚硝酸盐还原菌包括 Ignavibacterium sp.、Hyphomicrobium sp.、Alicycliphilus sp. 和 Anammox 细菌。Desulfovibrio sp.、Desulfosporosinus sp. 和 Thiobacillus sp. 与硫循环有关。Ignavibacterium sp.、Thiobacillus sp. 和 Desulfovibrio sp. 可能使用腐殖酸作为电子穿梭体与电极传递电子。可能的途径包括：（1）甲烷主要通过 M. oxyfera 细胞内歧化作用产生的氧气，被甲烷营养菌氧化为二氧化碳和溶解有机物。（2）异养反硝化菌利用溶解有机化合物将亚硝酸盐还原为氮气。（3）Desulfovibrio sp. 和 Desulfosporosinus sp. 将硫酸盐还原为硫离子。Thiobacillus sp. 以亚硝酸盐为电子受体将硫离子氧化为硫或硫酸盐。
