iTRAQ quantitative proteomic analysis reveals the pathways for methanation of propionate facilitated by magnetite
iTRAQ quantitative proteomic analysis reveals the pathways for methanation of propionate facilitated by magnetite
复制标题
iTRAQ 定量蛋白质组学分析揭示了磁铁矿促进丙酸盐甲烷化的途径
DOI：
10.1016/j.watres.2016.10.077
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发表时间：
2017-01-01
期刊：
影响因子：
12.8
通讯作者：
Luo, Gang
中科院分区：
文献类型：
--
作者：
Jing, Yuhang;Wan, Jingjing;Luo, Gang
丙酸甲烷化需要丙酸氧化菌和氢营养产甲烷菌的互养相互作用，这被称为种间电子传递。结果表明，添加10 mg/L的导电磁铁矿可使丙酸盐产甲烷速率提高44%左右，直接种间电子转移和种间H-2转移在理论上都是可行的。在长期运行的连续反应器中，也证明了磁铁矿促进的丙酸甲烷化。结果表明，添加磁铁矿的混合培养物的乙酸盐产甲烷速率高于不添加磁铁矿的混合培养物，而添加和不添加磁铁矿的混合培养物的H2-/CO2产甲烷速率相近。利用分子H-2的能力表明种间H-2转移在磁铁矿富集培养中发挥了作用，并且通过宏基因组测序还检测到与种间H-2转移相关的丙酸氧化细菌。元基因组测序分析也表明，Thauera，可能与直接种间电子转移，富集与磁铁矿的加入。首次应用于混合培养的iTRAQ定量蛋白质组学分析表明，磁铁矿诱导了丙酸甲烷化过程中各途径蛋白质表达水平的变化。丙酸代谢相关蛋白表达上调，主要来源于丙酸氧化菌，而丙酸氧化菌的直接种间电子传递能力尚未见报道。细胞色素c氧化酶也被认为是与直接种间电子转移有关的蛋白质，考虑到其在添加磁铁矿时的上调和来自Thauera。甲烷代谢中表达上调的蛋白质主要来源于甲烷八叠球菌，表达下调的蛋白质主要来源于甲烷八叠球菌。然而，与氢营养产甲烷相关的上调蛋白质既不来自甲烷八叠球菌也不来自甲烷菌，表明它们不参与直接的种间电子传递。氢营养型产甲烷菌，例如甲烷球菌属（Methanosphaerula）等，可能参与了物种间的直接电子转移。总体而言，本研究表明，直接种间电子转移和种间H-2转移过程中存在丙酸甲烷化促进磁铁矿。(C)2016爱思唯尔有限公司版权所有
Methanation of propionate requires syntrophic interaction of propionate-oxidizing bacteria and hydrogenotrophic methanogens, which is referred to as interspecies electron transfer. The present study showed that 10 mg/L conductive magnetite enhanced the methane production rate from propionate by around 44% in batch experiments, and both direct interspecies electron transfer and interspecies H-2 transfer were thermodynamically feasible with the addition of magnetite. The methanation of propionate facilitated by magnetite was also demonstrated in a long-term operated continuous reactor. The methane production rate from acetate by the enriched mixed culture with magnetite was higher than that without magnetite, while similar methane production rates were found from H-2/CO2 by the enriched mixed culture with and without magnetite. The ability to utilize molecular H-2 indicated interspecies H-2 transfer played a role in the enriched culture with magnetite, and propionate-oxidizing bacteria relating with interspecies H-2 transfer were also detected by metagenomic sequencing. Meta-genomic sequencing analysis also showed that Thauera, possibly relating with direct interspecies electron transfer, were enriched with the addition of magnetite. iTRAQ quantitative proteomic analysis, which was used in mixed culture for the first time, showed that magnetite induced the changes of protein expression levels involved in various pathways during the methanation of propionate. The up regulation of proteins involved in propionate metabolism were found, and they were mainly originated from propionate-oxidizing bacteria which were not reported to be capable of direct interspecies electron transfer until now. Cytochrome c oxidase was also revealed as the possible protein relating with direct interspecies electron transfer considering its up-regulation with the addition of magnetite and origination from Thauera. Most of the up-regulated proteins in methane metabolism were originated from Methanosaeta, while most of the enzymes with down-regulated proteins were originated from Methanosarcina. However, the up-regulated proteins relating with hydrogenotrophic methanogenesis were originated from neither Methanosaeta nor Methanosarcina, indicating they were not involved in direct interspecies electron transfer. The hydrogenotrophic methanogens, e.g. Methanospirillum, Methanosphaerula et al., might be involved in direct interspecies electron transfer. Overall, the present study showed that both direct interspecies electron transfer and interspecies H-2 transfer were present during methanation of propionate facilitated by magnetite. (C) 2016 Elsevier Ltd. All rights reserved.