One-carbon bioconversion based on microbial electrosynthesis

doi:10.12211/2096-8280.2025-078

Abstract

Abstract:

Microbial electrosynthesis (MES) stands as a cutting-edge and promising technology that harnesses the metabolic capabilities of microbial cells to drive the conversion of carbon dioxide (CO₂) into a diverse range of value-added chemicals, with electrons derived from the cathode serving as the critical reducing power. This innovative approach not only offers a potential solution to mitigate anthropogenic CO₂ emissions but also presents a sustainable route for the production of high-value compounds, bridging the gap between environmental remediation and industrial biotechnology. However, despite the significant progress made in recent years, several key limitations persist in the field of MES. A major hurdle lies in the incomplete mechanistic understanding of the underlying processes, particularly regarding the intricate interactions between the microbial cells and the electrode surfaces, as well as the precise regulatory mechanisms governing electron uptake and carbon fixation. Additionally, the efficient utilization of one-carbon conversion pathways from various substrates remains a challenge, with many pathways exhibiting suboptimal activity or being restricted to specific substrates, thereby limiting the versatility and applicability of MES systems. Given these constraints, a comprehensive analysis of different types of MES devices and their operational characteristics is of paramount importance. Each device configuration, whether single-chamber, dual-chamber, or more advanced designs, possesses unique features that influence mass transfer, electron transfer efficiency, and microbial growth conditions. By gaining a deep understanding of these device-specific properties, researchers can tailor and optimize one-carbon bioconversion pathways to match the requirements of different substrates, thereby maximizing the overall efficiency and productivity of the MES process. This customization of pathways based on device characteristics represents a crucial step towards unlocking the full potential of MES technology. Furthermore, the selection and implementation of nanomaterials in MES systems are closely intertwined with the design and basic principles of the MES devices. Nanomaterials, with their unique physicochemical properties such as high surface area, excellent conductivity, and tunable surface functionalities, have emerged as promising modifiers to enhance MES performance. However, the effectiveness of nanomaterials is highly dependent on the specific device architecture and operational parameters. For instance, in devices with limited mass transfer, nanomaterials that facilitate electron transfer at the electrode-microbe interface may be more beneficial, whereas in systems where microbial adhesion is a limiting factor, nanomaterials that promote biofilm formation could be prioritized. Thus, a thorough analysis of the interplay between MES devices, nanomaterials, and their strengthening mechanisms is essential to develop synergistic strategies for efficiency enhancement. In this context, we delve into the analysis of various MES device configurations, elucidating their core operational principles and highlighting their respective advantages and limitations. Concurrently, we evaluate the strengths and weaknesses of different biological one-carbon conversion pathways, considering factors such as energy requirements, carbon flux distribution, and product specificity. Moreover, we explore the multifaceted roles of nanomaterials in augmenting MES efficiency, with a particular focus on their ability to modulate extracellular electron transfer (EET) processes. Nanoparticles have been shown to exert significant effects on the expression of functional genes involved in EET, thereby enhancing the electron uptake capacity of microbial cells and promoting more efficient communication between the microbes and the electrodes. Despite the current challenges, including low Faradaic efficiencies, suboptimal substrate conversion rates, and limited product synthesis yields that relegate MES to the early stages of development, the technology holds immense promise as one of the most viable CO₂ conversion strategies for the future. Its inherent sustainability, coupled with the potential for integration with renewable energy sources to power the electrochemical reactions, positions MES as a key player in the transition towards a low-carbon economy. By addressing the existing limitations through interdisciplinary research that combines microbiology, electrochemistry, materials science, and metabolic engineering, MES has the potential to make a substantial contribution to advancing sustainable biotechnology strategies and realizing a more environmentally benign and resource-efficient future.

Key words: microbial electrosynthesis, CO₂ fixation, electron transfer, nanobiotechnology, biosynthesis

摘要：

微生物电合成（Microbial electrosynthesis， MES）是一项具有广阔前景的技术，主要依赖微生物通过阴极提供的电子将二氧化碳转化为增值化学品。然而，目前对MES的机制分析以及不同底物的一碳转化利用尚存在一定的局限性。因此，研究不同类型的MES装置，并根据其特性提供适宜的底物一碳生物转化路径至关重要。此外，各类MES装置及其基本原理也会影响纳米材料的选择与其强化机制。本文通过对不同MES装置及其核心基本原理的分析，探讨了不同生物一碳转化路径的优缺点，同时研究了纳米材料在MES过程中的强化机制，以期提高MES的效率，因为纳米颗粒在电子转移中对功能基因的表达起着重要作用。尽管MES目前仍处于初步开发阶段，其法拉第效率、底物转化路径及产物合成效率相对较低，但依然是未来最具潜力的二氧化碳转化技术，对推动低碳未来的可持续生物技术战略具有重要意义。

关键词: 微生物电合成, CO₂固定, 电子传递, 纳米生物技术, 生物合成

CLC Number:

Q816

LI Yixin, DONG Rong, JIE Yinuo, WANG Yuanpeng, CAO Mingfeng. One-carbon bioconversion based on microbial electrosynthesis[J]. Synthetic Biology Journal, DOI: 10.12211/2096-8280.2025-078.

李逸鑫, 董蓉, 解一诺, 王远鹏, 曹名锋. 基于微生物电合成的一碳生物转化[J]. 合成生物学, DOI: 10.12211/2096-8280.2025-078.

Figures/Tables 7

References 95

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对比	直接MES	间接MES
能量利用效率	能量传递路径短，电能直接转化化学能，理论能量损耗较少，单步转化效率高；受副反应影响，实际有效能量利用率易降低，且产物多为低附加值小分子，单位产物能量密度较低。	能量传递路径长，多步转化存在能量损耗，整体效率偏低；微生物可定向合成高附加值产物，单位产物能量密度高，能量利用的经济性效率更优。
技术优点	反应速率快，操作可控性强，体系稳定性高，设备结构简单	产物多样性与高附加值，产物选择性极高，CO₂转化彻底，低能耗适配性
技术缺点	产物附加值低，产物选择性差，高电位需求	反应速率慢，体系稳定性差，操作复杂度高，设备集成复杂
核心工艺关键	优化电极材料、优化电子传递效率	优化电催化-微生物催化传质

对比	直接MES	间接MES
能量利用效率	能量传递路径短，电能直接转化化学能，理论能量损耗较少，单步转化效率高；受副反应影响，实际有效能量利用率易降低，且产物多为低附加值小分子，单位产物能量密度较低。	能量传递路径长，多步转化存在能量损耗，整体效率偏低；微生物可定向合成高附加值产物，单位产物能量密度高，能量利用的经济性效率更优。
技术优点	反应速率快，操作可控性强，体系稳定性高，设备结构简单	产物多样性与高附加值，产物选择性极高，CO₂转化彻底，低能耗适配性
技术缺点	产物附加值低，产物选择性差，高电位需求	反应速率慢，体系稳定性差，操作复杂度高，设备集成复杂
核心工艺关键	优化电极材料、优化电子传递效率	优化电催化-微生物催化传质

菌种	类型	底物	产物	产率（气体mmol/d或者溶液mmol/(L·d))	法拉第效率	参考文献
Methanococcus vannielii	直接式MES	CO₂	CH₄	0.185±0.012	58.9±0.8	[3]
Clostridium ragsdalei	直接式MES	CO₂	乙酸	0.5	38	[46]
Ralstonia eutropha	直接式MES	CO₂	PHB	87.54 mg/L	n.a.	[47]
微生物群落	直接式MES	CO₂/甲酸	乙酸	0.269 +/- 0.009 g·L^-1·day^-1	92.54%	[48]
微生物群落	直接式MES	CO₂/甲醇	丁酸	8.6 +/- 0.2 g·L^-1	n.a.	[49]
Saccharomyces cerevisiae	间接式MES	CO₂-乙酸	葡萄糖	1.81±0.14 g·L^-1	n.a.	[43]

菌种	类型	底物	产物	产率（气体mmol/d或者溶液mmol/(L·d))	法拉第效率	参考文献
Methanococcus vannielii	直接式MES	CO₂	CH₄	0.185±0.012	58.9±0.8	[3]
Clostridium ragsdalei	直接式MES	CO₂	乙酸	0.5	38	[46]
Ralstonia eutropha	直接式MES	CO₂	PHB	87.54 mg/L	n.a.	[47]
微生物群落	直接式MES	CO₂/甲酸	乙酸	0.269 +/- 0.009 g·L^-1·day^-1	92.54%	[48]
微生物群落	直接式MES	CO₂/甲醇	丁酸	8.6 +/- 0.2 g·L^-1	n.a.	[49]
Saccharomyces cerevisiae	间接式MES	CO₂-乙酸	葡萄糖	1.81±0.14 g·L^-1	n.a.	[43]

对比	电极修饰	细胞修饰
作用对象	优点：作用于电极这一非生物组件，不依赖微生物种类，可适配任意电活性微生物，普适性强缺点：仅优化外部界面，无法改变微生物自身的电子传递能力	优点：直接作用于微生物，从生物核心层面强化功能，可针对性解决微生物自身电子传递弱、代谢活性低的问题缺点：微生物增殖过程可能会脱落
效率提升机制	优点：通过两种路径高效提升效率，包括物理结构优化提升微生物负载量和功能协同，同时提供电子与碳源，机制清晰且易量化缺点：机制单一，无法干预胞内代谢	优点：机制更全面，覆盖电子传递和能量代谢双维度，可从多环节突破效率瓶颈。缺点：机制复杂且部分未明确，难以精准调控单一机制
材料稳定性	优点：部分纳米材料化学稳定性高，在中性电解液中可稳定存在缺点：易出现“功能失效”问题：物理损耗（纳米颗粒团聚后从电极表面脱落，导致比表面积下降）；生物污染（微生物膜覆盖修饰层，阻断电子传递通道）；化学腐蚀	优点：无材料脱落问题，纳米材料与微生物形成 “生物 - 材料复合体”（如 CDs 被细胞内化、聚吡咯涂覆细胞表面），随微生物增殖同步传递，材料利用率高。缺点：纳米材料可能影响微生物活性：毒性风险；生物相容性
与其他策略协同性	可与光电耦合直接协同，无需调整	与合成生物学强化协同性极强，可形成基因改造-材料修饰的双重强化