产乙酸菌与一碳气体生物转化：从基础到应用

Acetogenic bacteria and one-carbon gas biotransformation: from fundamental research to applications

摘要:

一碳(C1)气体(如CO、CO₂及其与H₂组成的合成气)的资源化利用，是应对全球气候变化及构建可持续循环经济的关键路径。产乙酸菌作为一类能够通过伍德-永达尔途径(Wood-Ljungdahl pathway, WLP)高效同化C1气体的专性厌氧微生物，为生物固碳提供了一条高碳原子经济性的天然转化通道。本文系统综述了产乙酸菌在C1气体转化领域从基础研究到工业应用的最新进展。首先，本文阐释了产乙酸菌与C1气体之间的代谢耦合关系，深入解析了其利用C1底物的生化基础。在基础研究方面，重点探讨了近年来在能量守恒机制以及代谢流调控方面的突破；同时，总结了以CRISPR-Cas为代表的先进遗传操作系统的开发，以及如何利用其提升乙酸、乙醇等天然代谢产物的产量，推动产乙酸菌向生产丁醇、3-羟基丁酸(3-hydroxybutyric acid, 3-HB)等高附加值化学品的“底盘细胞”转变。最后，本文剖析了产乙酸菌气态发酵在走向工业化规模放大时所面临的气液传质受限、能量供应瓶颈等工程挑战，并对其在助力实现“双碳”目标与下一代绿色生物制造中的广阔应用前景进行了展望。

Abstract:

The valorization of one-carbon (C1) gases such as CO, CO₂, and syngas (a mixture with H₂) represents a promising route for responding to global climate change and establishing a sustainable circular economy. Acetogens, a group of obligate anaerobic microorganisms capable of efficiently assimilating C1 gases via the Wood-Ljungdahl pathway (WLP), offer a natural conversion route with high carbon atom economy for biological carbon fixation. This paper provides a systematic review of the latest advancements in C1 gases conversion by acetogens, spanning from fundamental research to industrial applications. We first elucidate the metabolic coupling between acetogens and C1 gases, delving into the biochemical basis for utilizing C1 sources. In terms of fundamental research, we highlight recent breakthroughs in energy conservation mechanisms and metabolic flux regulation. Then, we summarize how the development of advanced genetic manipulation systems, exemplified by CRISPR-Cas tools, has enhanced the titers of natural products such as acetate and ethanol and accelerated the transformation of acetogens into chassis cells for the production of high-value chemicals such as butanol and 3-hydroxybutyrate. Finally, this review analyzes the engineering challenges, including gas-liquid mass transfer limitations and energy supply bottlenecks, associated with the scale-up of gas fermentation while offering a perspective on the broad application prospects of acetogens in achieving carbon peaking and carbon neutrality goals and advancing next-generation green biomanufacturing.