Rewiring carbon flow in Synechocystis PCC 6803 for a high rate of CO2-to-ethanol under an atmospheric environment

Frontiers in Microbiology

Microbiology

Junhua Wu¹  Haiyan Qiu¹  Penglin Ye²  Zhen Fang²  Huayou Chen³  E-Bin Gao⁴ 

[1] Ningbo Women and Children's Hospital, Ningbo, China;School of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu, China;School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, China;School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, China;School of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu, China;

关键词: cyanobacteria;    metabolic engineering;    cofactor regeneration;    CO fixation;    photosynthetic cell factory;   

DOI  :  10.3389/fmicb.2023.1211004

 received in 2023-04-24, accepted in 2023-05-09,  发布年份 2023

来源: Frontiers

【 摘 要 】

Cyanobacteria are an excellent microbial photosynthetic platform for sustainable carbon dioxide fixation. One bottleneck to limit its application is that the natural carbon flow pathway almost transfers CO2 to glycogen/biomass other than designed biofuels such as ethanol. Here, we used engineered Synechocystis sp. PCC 6803 to explore CO2-to-ethanol potential under atmospheric environment. First, we investigated the effects of two heterologous genes (pyruvate decarboxylase and alcohol dehydrogenase) on ethanol biosynthesis and optimized their promoter. Furthermore, the main carbon flow of the ethanol pathway was strengthened by blocking glycogen storage and pyruvate-to-phosphoenolpyruvate backflow. To recycle carbon atoms that escaped from the tricarboxylic acid cycle, malate was artificially guided back into pyruvate, which also created NADPH balance and promoted acetaldehyde conversion into ethanol. Impressively, we achieved high-rate ethanol production (248 mg/L/day at early 4 days) by fixing atmospheric CO2. Thus, this study exhibits the proof-of-concept that rewiring carbon flow strategies could provide an efficient cyanobacterial platform for sustainable biofuel production from atmospheric CO2.

【 授权许可】

Unknown   
Copyright © 2023 Gao, Wu, Ye, Qiu, Chen and Fang.

【 图 表 】

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