Abstract:

One-carbon (C1) compounds—including CO₂, CO, methane, methanol, and formate—have emerged as strategic feedstocks for next-generation biomanufacturing owing to their abundance, economic viability, and renewability. However, the efficient biological conversion of C1 substrates into valuable products is hampered by several fundamental challenges,including the low intrinsic efficiency of natural carbon fixation pathways, the thermodynamic and kinetic barriers in engineering efficient de novo artificial assimilation routes, the cytotoxic effects of reactive intermediates like formaldehyde, and the generally suboptimal industrial robustness and slow growth of both native and synthetic C1-utilizing microbes. Recent breakthroughs in synthetic biology and metabolic engineering have substantially mitigated these constraints, thereby accelerating C1 bioconversion and establishing a novel paradigm for carbon-neutral, green biomanufacturing. This review systematically examines state-of-the-art strategies and technological milestones reported between 2022 and 2025, with a focus on (i) Metabolic rewiring of native C1-utilizing microorganisms to enhance both C1-assimilation efficiency and product-synthesis capacity, (ii) de novo design of non-natural C1 assimilation pathways​ to provide more efficient route for the construction of C1-utilizing cell factories, and (iii) engineering artificial C1-utilizing cell factories through reconstituting natural or artificial C1 assimilation modules in well-established industrial fermentation strains to establish platform strains for C1-based bioproduction. Moving beyond strategy description, we provide a comparative analysis of the metabolic characteristics, advantages, and limitations of key natural and synthetic C1 assimilation pathways. We further evaluate the applicability of various microbial hosts for the synthesis of target products ranging from biofuels and bulk chemicals to specialized metabolites. A critical discussion addresses the persistent technical bottlenecks, such as low activity of key C1 assimilation enzymes, poor biomanufacturing capabilities of natural C1-utilizing bacteria, and the challenges in achieving high flux through artificial pathways in vivo. Finally, we explore the synergistic potential of integrated solutions—combining adaptive laboratory evolution, enzyme engineering, computational modeling, and systems-level analysis—to boost C1 utilization. We conclude by highlighting the transformative role of interdisciplinary convergence and artificial intelligence in accelerating the design-build-test-learn cycle, thereby paving the way for a sustainable, C1-driven bioeconomy.

Key words: one-carbon compounds, methylotrophy, synthetic biology, metabolic engineering, green biomanufacturing

摘要：

一碳化合物（C1，包括CO₂、CO、甲烷、甲醇及甲酸）作为重要的含碳资源，凭借其来源广泛、经济及可再生特性，已成为生物制造领域的新型战略原料。近年来，合成生物学与代谢工程技术的突破性进展显著推动了C1化合物的生物转化路径创新，为碳中和目标下的绿色生物制造开辟了新范式。本文聚焦天然C1利用微生物的代谢网络优化、非天然C1利用途径的开发以及人工合成甲基营养菌的理性设计，系统比较评估了不同微生物底盘在C1生物转化中的应用潜力及关键C1同化途径的代谢特征，并综述了2022-2025年间该领域的前沿策略与技术成果。进一步对比分析了甲基营养菌的应用领域，探讨了各类宿主在产物合成中的适配性，探讨了当前存在的生物固碳效率低、人工固碳途径在体内难以高效运行、毒性中间体限制甲醇同化、人工甲基营养菌生长缓慢等难题。在此基础上，进一步讨论了实验室进化、酶工程、人工途径设计等多种手段协同提升C1利用效率的潜力，以及多学科交叉与人工智能在该领域发展中的重要作用，以期为C1驱动的可持续生物经济体系构建提供理论支撑。

关键词: 一碳化合物, 甲基营养型, 合成生物学, 代谢工程, 绿色生物制造