Synthetic Biology Journal ›› 2023, Vol. 4 ›› Issue (6): 1178-1190.DOI: 10.12211/2096-8280.2023-045

• Invited Review • Previous Articles     Next Articles

Progress on bio-fixation and utilization of CO2 in acetogens driven by chemical energy

Zhiqiong WEN1, Yuzhen LI1, Jin′gang ZHANG2, Feifei Wang2, Xiaoqing MA1, Fuli LI1   

  1. 1.CAS Key Laboratory of Biofuel,Qingdao C1 Refinery Research Engineering Center,Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences,Qingdao 266101,Shandong,China
    2.Shandong Rongxin Group Co. ,Ltd,Jining 273517,Shandong,China
  • Received:2023-06-30 Revised:2023-09-14 Online:2024-01-19 Published:2023-12-31
  • Contact: Fuli LI

化能驱动的产乙酸菌转化利用CO2研究进展

文志琼1, 李煜真1, 张金刚2, 王菲菲2, 马小清1, 李福利1   

  1. 1.中国科学院青岛生物能源与过程研究所,中国科学院生物燃料重点实验室,青岛市碳一炼制工程研究中心,山东 青岛 266101
    2.山东荣信集团有限公司,山东 济宁 273517
  • 通讯作者: 李福利
  • 作者简介:文志琼(1993—),女,博士研究生。研究方向为厌氧梭菌生理生化。E-mail:wenzq@qibebt.ac.cn
    李福利(1975—),男,研究员,博士生导师。研究方向为厌氧微生物能量代谢,一碳生物转化合成生物学。E-mail:lifl@qibebt.ac.cn
  • 基金资助:
    国家自然科学基金联合基金重点项目(U22A20425);济宁市重点研发计划(2022JBZP008);山东能源研究院专项(SEI S202104)

Abstract:

To promote the development of carbon utilization and biomanufacturing industry, one-carbon substrates are expected to be the next generation feedstocks and attracted much attention because of their abundance and availability for value-added products. Acetogens can naturally use syngas (CO, CO2 and H2) through the classical Wood-Ljungdahl pathway to support their growth and produce value-added chemicals such as acetic acid and ethanol. Compared to chemical catalysis, this biorefinery process has the advantages of low requirements for feedstocks, mild reaction conditions and high product selectivity. In some acetogens, both CO and H2 can act as energy sources to provide the reducing equivalents required for growth and metabolism during gas fermentation. In particular, acetogens utilizing CO and H2 have distinct patterns of energy metabolism. Compared to H2, CO is a more thermodynamically favorable energy source for gas fermentation. In general, different acetogens during autotrophic growth with syngas as carbon source and energy source can produce different products. However, the low solubility of gases in liquid medium, as well as the poor mass transfer and diffusion, limits the energy supply during the fermentation, resulting in slow growth rate of microorganisms, low raw material utilization, and low target product yield. Therefore, improving syngas utilization efficiency and enlarging products spectrum of acetogens are both of great importance to meet the demands of industrialization. In recent years, with the development of synthetic biology and molecular genetic tools, modification of acetogen strains has been well designed. In this review, we briefly described the natural metabolic pathways such as ethanol and acetone metabolism pathways, and summarized the progress of acetogens in autotrophic fermentation using syngas as energy sources to produce value-added products such as ethanol, 2,3-butanediol, acetone and isoprepanol. For engineering the acetogens, we summarized the pathways to produce natural and non-natural chemicals. Finally, the energy capture and utilization of acetogens was prospected, with the aim to facilitate the future advancement of biorefineries.

Key words: acetogen, C1-gas, chemoautotrophy, gene engineering, energy conservation

摘要:

利用微生物发酵一碳气体生产燃料和高值化学品,是实现碳资源回收利用和绿色生物制造的重要途径之一。产乙酸菌可利用CO或H2为能量来源,通过伍德-永达尔(Wood-Ljungdahl)途径固定CO2,维持自身代谢,并生产乙酸、乙醇等高附加值产品。相较于化学催化而言,该生物催化过程对原料气体比例要求不高、反应条件温和、产物选择性高。在气体发酵中,CO和H2均可作为菌株生长和代谢的能量来源,二者具有不同的能量代谢模式。同时,不同的产乙酸菌代谢产物也不相同。发酵过程中气体溶解度低限制了能量供给,导致微生物生长速率慢、原料利用率低以及目标产物产量低等问题。提高气体利用效率和扩大产乙酸菌的产物谱,是面向产业化应用的必然要求。本文简述了产乙酸菌的伍德-永达尔途径、产乙酸途径和产乙醇途径等天然代谢途径,从分子改造的角度总结了产乙酸菌利用一碳气体发酵生产高附加值产品如乙醇、2,3-丁二醇、丙酮、异丙醇等的相关研究进展,并从提高能量供给和产物选择性的角度进行了总结。最后,本文以能量代谢为切入点对产乙酸菌转化一碳气体进行了展望,以期为未来的生物制造提供参考。

关键词: 产乙酸菌, 一碳气体, 化能自养, 基因工程, 能量守恒

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