Engineered Bacteria Upcycle Waste Carbon Dioxide into Chemicals for Numerous Applications

Bacteria can break down lactose to form yogurt and sugar to produce beer. Currently, scientists led by Northwestern University and LanzaTech have utilized bacteria to break down discarded carbon dioxide (CO₂) to create beneficial industrial chemicals.

In a new pilot study, the scientists chose, engineered and improved a bacteria strain and then effectively showed its ability to turn CO₂ into acetone and isopropanol (IPA). 

Besides eliminating greenhouse gases from the air, this new gas fermentation process also does not use fossil fuels, which are normally required to produce acetone and IPA.

After carrying out life-cycle analysis, the researchers discovered the carbon-negative system could decrease greenhouse gas emissions by 160% as compared to traditional methods if extensively adopted.

The research was published in the February 21^st issue of the journal Nature Biotechnology.

The accelerating climate crisis, combined with rapid population growth, pose some of the most urgent challenges to humankind, all linked to the unabated release and accumulation of CO₂ across the entire biosphere.

Michael Jewett, Study Co-Senior Author, Northwestern University

“By harnessing our capacity to partner with biology to make what is needed, where and when it is needed, on a sustainable and renewable basis, we can begin to take advantage of the available CO₂ to transform the bioeconomy,” Michael Jewett added.

Jewett is the Walter P. Murphy Professor of Chemical and Biological Engineering at Northwestern’s McCormick School of Engineering and director of the Center for Synthetic Biology. He co-led the research with Michael Koepke and Ching Leang, both scientists at LanzaTech.

Essential industrial bulk and platform chemicals, IPA and acetone, are found virtually everywhere, with a combined worldwide market reaching $10 billion.

Extensively used as an antiseptic and disinfectant, IPA is the foundation for one of the two World Health Organization-suggested sanitizer formulas, which are very effective in destroying the SARS-CoV-2 virus. While acetone is a solvent for numerous plastics and synthetic fibers, cleaning tools, thinning polyester resin and nail polish remover.

While these chemicals are extremely valuable, they are produced from fossil resources, resulting in climate-warming CO₂ emissions.

To produce these chemicals in a more sustainable manner, the team created a new gas fermentation method. They began with Clostridium autoethanogenum, an anaerobic bacterium developed at LanzaTech. Then, the scientists used artificial biology tools to reprogram the bacterium to ferment CO₂ to create IPA and acetone.

These innovations, led by cell-free strategies that guided both strain engineering and optimization of pathway enzymes, accelerated time to production by more than a year.

Michael Jewett, Study Co-Senior Author, Northwestern University

The Northwestern and LanzaTech teams believe that the engineered strains and fermentation process will be extended to an industrial scale. The method also could be applied to formulate simplified processes for producing other useful chemicals.

This discovery is a major step forward in avoiding a climate catastrophe. Today, most of our commodity chemicals are derived exclusively from new fossil resources such as oil, natural gas, or coal. Acetone and IPA are two examples with a combined global market of $10 billion. The acetone and IPA pathways developed will accelerate the development of other new products by closing the carbon cycle for their use in multiple industries.

Jennifer Holmgren, CEO, LanzaTech

Jewett is a member of the Chemistry of Life Processes Institute, Simpson Querrey Institute for BioNanotechnology, and the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

The study received support from the U.S. Department of Energy (DOE) Bioenergy Technologies Office (award numbers DE-EE0007566 and CRADA/NFE-16-06364), DOE Office of Science, Biological and Environmental Research Division, Genomic Science Program (award numbers DE-SC0018249 and FWP ERKP903), the David and Lucile Packard Foundation and the Camille Dreyfus Teacher-Scholar Program.

Journal Reference:

Liew, F.E., et al. (2022) Carbon-negative, scaled-up production of acetone and isopropanol by gas fermentation. Nature Biotechnology. doi.org/10.1038/s41587-021-01195-w.

Source: https://northwestern.edu