State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environment Sciences, Beijing 100012, PR China; Research Center of Environmental Pollution Control Engineering Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; School of Environment, Tsinghua University, Beijing 100084, PR China.
China Construction Eco-environmental Group CO.,LTD, Beijing 100037, PR China.
J Environ Manage. 2023 Jan 15;326(Pt B):116732. doi: 10.1016/j.jenvman.2022.116732. Epub 2022 Nov 16.
Direct interspecies electron transfer (DIET) stimulated by conductive materials (CMs) enables intercellular metabolic coupling that can address the unfavorable thermodynamical dilemma inherent in anaerobic digestion (AD). Although the DIET mechanism and stimulation have been extensively summarized, the methanogenesis contribution, characterization techniques, and downstream processes of CMs-led DIET in AD are surprisingly under-reviewed. Therefore, this review aimed to address these gaps. First, the contribution of CMs-led DIET to methanogenesis was re-evaluated by comparing the effect of various factors, including volatile fatty acids, free ammonia, and functional enzymes. It was revealed that AD systems are usually intricate and cannot allow the methanogenesis stimulation to be singularly attributed to the establishment of DIET. Additionally, considerable attention has been attached to the characterization of DIET occurrence, involving species identification, gene expression, electrical properties, cellular features, and syntrophic metabolism, suggesting the significance of accurate characterization methods for identifying the syntrophic metabolism interactions. Moreover, the type of CMs has a significant impact on AD downstream processes involving biogas purity, sludge dewaterability, and biosolids management. Finally, the central bottleneck consists in building a mathematical model of DIET to explain the mechanism of DIET in a deeper level from kinetics and thermodynamics.
直接种间电子转移（DIET）受导电材料（CMs）的刺激，能够实现细胞间的代谢偶联，从而解决厌氧消化（AD）中固有的不利热力学困境。尽管 DIET 机制和刺激已经被广泛总结，但 CMs 介导的 DIET 在 AD 中的产甲烷作用、特征化技术和下游过程却令人惊讶地被忽视了。因此，本综述旨在解决这些空白。首先，通过比较各种因素（包括挥发性脂肪酸、游离氨和功能酶）的影响，重新评估了 CMs 介导的 DIET 对产甲烷作用的贡献。结果表明，AD 系统通常很复杂，不能将产甲烷作用的刺激单一归因于 DIET 的建立。此外，人们对 DIET 发生的特征化给予了相当大的关注，涉及物种鉴定、基因表达、电特性、细胞特征和共代谢，这表明准确的特征化方法对于识别共代谢相互作用的重要性。此外，CMs 的类型对 AD 的下游过程有重大影响，包括沼气纯度、污泥脱水性能和生物固体管理。最后，中心瓶颈在于构建 DIET 的数学模型，从动力学和热力学的角度更深入地解释 DIET 的机制。
