New insights into the mechanisms underlying biochar-assisted sustained high-efficient co-digestion: Reducing thermodynamic constraints and enhancing extracellular electron transfer flux
New insights into the mechanisms underlying biochar-assisted sustained high-efficient co-digestion: Reducing thermodynamic constraints and enhancing extracellular electron transfer flux
复制标题
对生物炭辅助持续高效共消化机制的新见解：减少热力学约束并增强细胞外电子转移通量
DOI：
10.1016/j.scitotenv.2021.151416
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发表时间：
2022
影响因子：
9.8
通讯作者：
Rong Chen
中科院分区：
文献类型：
--
作者：
Qian Li;Yaqian Liu;Wenyu Gao;Gaojun Wang;Mawuli Dzakpasu;Yu-You Li;Rong Chen
为了明确生物炭在垃圾活性污泥（WAS）和食物垃圾（FW）厌氧共消化中的作用，结合热力学、胞外电子传递通量和微生物群落分析进行了批量试验。与对照组相比，生物炭在三个阶段均显著促进了共消化，但其持续促进作用主要集中在挥发性脂肪酸（VFAs）的合成甲烷生成上。热力学分析证实，生物炭可以缓解物种间氢转移（IHT）过程中高氢分压的限制，醋酸酯和丙酸酯合成气产甲烷的热力学窗口分别扩大了137%和92%。同时，由于生物炭的氧化还原能力（4.85和0.35 μmol e−/g），得到醋酸盐和丙酸盐合成气产甲烷的直接种间电子转移（DIET）通量的等效电流分别为1.0 × 10−4A和0.9 × 10−4A，是IHT的108倍。值得注意的是，能参与DIET的功能微生物如甲烷菌仅富集在生物炭表面，悬浮污泥中甲烷热菌的优势可能表明IHT仍是合成气产甲烷的主要途径。然而，由生物炭表面氧化还原活性部分触发的DIET和通过减轻热力学限制而增强的IHT协同促进了合成气产甲烷。
To clarify the roles of biochar in the anaerobic co-digestion of waste activated sludge (WAS) and food waste (FW), batch tests were conducted coupled with thermodynamics, extracellular electron transfer flux and microbial community analysis. Compared with the control group, biochar significantly facilitated the co-digestion at three periods, but its sustainable facilitation was mainly in the syntrophic methanogenesis of volatile fatty acids (VFAs). The thermodynamic analysis confirmed that biochar could alleviate limitations imposed by high hydrogen partial pressure during interspecies hydrogen transfer (IHT), the thermodynamic windows was expanded 137% and 92% in the syntrophic methanogenesis of acetate and propionate, respectively. Meanwhile, due to the redox capacity of biochar (4.85 and 0.35 μmol e−/g biochar), the equivalent current of direct interspecies electron transfer (DIET) flux for syntrophic methanogenesis of acetate and propionate obtained were 1.0 × 10−4A and 0.9 × 10−4A, which were 108times than that of IHT. It should be noticed that the functional microorganisms likeMethanosarcinawhich could participate DIET were only enriched on the surface of biochar, the dominantMethanothermobacterin suspended sludge probably indicate IHT was still the main pathway for syntrophic methanogenesis. Nevertheless, the DIET triggered by the redox-active moieties on the surface of biochar and the enhanced IHT by alleviating thermodynamic restrictions, promoted the syntrophic methanogenesis synergistically.