Direct Ocean Capture: CO2 Dissolved in Seawater Can Be Captured and Used as Feedstock for Plastic for a Double Decarbonization Effect: Chinese Study and Demo Project

     With a new paper published in Nature Catalysis, scientists from the Shenzhen Institutes of Advanced Technology of the Chinese Academy of Sciences and the University of Electronic Science and Technology of China have developed a process that efficiently transforms CO2 from deep in the oceans into sustainable plastics. The method involves capturing dissolved CO2 from seawater. It is a method of direct ocean capture (DOC).

"Renewable electricity-driven capture and conversion of oceanic dissolved inorganic carbon into value-added chemicals offers a sustainable route towards negative carbon emissions and a circular carbon economy," wrote the researchers.

     The method recycles ocean carbon by capturing it and converting it into biochemicals via a "decoupled electro-biocatalytic hybrid process."  The results of the demonstration included a capture rate of 70% while operating continuously for up to 536 hours. The estimated cost of carbon capture was revealed to be around $230 per ton of CO2. That is lower than direct air capture but much higher than point-source carbon capture, which ranges from $15 per ton for highly concentrated industrial sources, and $40-120 per ton for dilute gas streams from sources such as power plants.

"This is the first demonstration that's going from ocean carbon dioxide all the way to a usable feedstock for bioplastic, said Dr. Chengxiang Xiang, staff scientist for the Joint Center for Artificial Photosynthesis at California Institute of Technology. He noted that the primary goal of the study was "taking that CO2 and turning it into a bioplastic monomer with promising stability and economics."

     The research team developed an artificial ocean carbon recycling system that converts the captured CO2 into succinic acid, a key monomer for the biodegradable plastic polybutylene succinate (PBS). The new process involves electrochemistry with microbial fermentation in a reactor. The system utilizes engineered microbes that can be tailored to produce a range of valuable industrial chemicals, such as lactic acid, alanine, and 1,4-butanediol.

 

 

  

 

 

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Scientists achieve incredible breakthrough using seawater: 'This is the first demonstration'. Matthew Swigonski. The Cool Down. November 10, 2025. Scientists achieve incredible breakthrough using seawater: 'This is the first demonstration'

Artificial Ocean Carbon Recycling System Converts Seawater CO2 into Valuable Chemicals. the Shenzhen Institutes of Advanced Technology of the Chinese Academy of Sciences (CAS). October 13, 2025. Nature Catalysis----Shenzhen Institutes of Advanced Technology

Efficient and scalable upcycling of oceanic carbon sources into bioplastic monomers. Chengbo Li, Mingming Guo, Bo Yang, Yuan Ji, Jing Zhang, Liujiang Zhou, Chunxiao Liu, Haoyuan Wang, Jiawei Li, Weiqing Xue, Xinyan Zhang, Hongliang Zeng, Yanjiang Wang, Donghao Zhao, Kexin Zhong, Shanshan Pi, Minzhe Hei, Xu Li, Qiu Jiang, Tingting Zheng, Xiang Gao & Chuan Xia. Nature Catalysis volume 8, pages1023–1037 (October 6, 2025). Efficient and scalable upcycling of oceanic carbon sources into bioplastic monomers | Nature Catalysis