A new technology has been developed that uses two types of microorganisms in stages to convert carbon dioxide, a major contributor to climate change, into eco-friendly fuel.
The Ulsan National Institute of Science and Technology (UNIST) announced on the 28th that Professor Kim Jin-hyun of the Department of Materials Science and Engineering, in collaboration with a research team from the University of California, Berkeley (UC Berkeley), has developed a continuous microbial process system that converts carbon dioxide into the eco-friendly fuel butanol. The research findings were published in the international journal ‘Bioresource Technology’ on the 24th of last month (local time).
To mitigate climate change, efforts are ongoing to convert the greenhouse gas carbon dioxide into various useful substances. A process designed for microorganisms to absorb CO2 and produce useful materials through metabolism is eco-friendly and consumes less energy. It also eliminates the need for expensive precious metal catalysts.
The research team created a microbial conversion system that links two microorganisms in stages, much like a factory assembly line. This approach was taken because microorganisms that directly convert carbon dioxide to butanol have low efficiency and are difficult to control, limiting their commercialization.
A “division of labor” was established where an acetogen (*Sporomusa ovata*) consumes carbon dioxide to produce acetic acid (CH3COOH), which is then taken up by *E. coli* to complete the conversion into butanol (C4H9OH).
The team genetically engineered the *E. coli* to increase butanol production efficiency by 3.8 times. Typical *E. coli* do not readily consume acetic acid, and even when they do, they use the resulting energy primarily for survival, leading to poor butanol production efficiency. The researchers modified the bacteria to prefer consuming acetic acid and to channel its energy into producing butanol.
The developed process stably produced butanol for over 90 hours with only carbon dioxide and hydrogen as inputs, requiring no external carbon source. Hydrogen is a material used by the acetogen to create acetic acid. The system produced 4.8 milligrams (mg) of butanol per liter of culture medium per hour.
The research team explained, “While it is not yet economically viable, we have established a foundational and scalable system for converting carbon dioxide into butanol.”
Professor Kim stated, “We have stably linked two continuous culture reactors where raw material supply and product production occur uninterruptedly.” He added, “By increasing microbial metabolic efficiency and optimizing the process, this could become an alternative to replace fossil fuels and accelerate the era of carbon neutrality.”
Read the full article here.
Original title: Microbial assembly line turns carbon dioxide into butanol fuel
Author: Byeongku Lee
Link: DongA Science