Researchers unveil new LCA carbon capture technology to reduce emissions by 160%
22 Feb 2022 --- Researchers led by LanzaTech, Northwestern University and Oak Ridge National Lab (ORNL) in the US have developed a new process to convert waste gas like emissions from heavy industry or syngas generated from any biomass source into either acetone or isopropanol (IPA). These substances can be used as solvents, antiseptics, disinfectants and detergents for commercial plastics.
The companies’ methods, including a pilot-scale demonstration and life cycle analysis (LCA) showing economic viability, are published in Nature Biotechnology.
The new technology uses greenhouse gas (GHG) emissions destined for the atmosphere, avoids burning fossil fuels and removes carbon dioxide from the air, says the collaboration. According to LCA results, this carbon-negative platform could reduce GHG by over 160%, playing a “critical role” in helping the US reach a net-zero emissions economy.
“This discovery is a major step forward in avoiding a climate catastrophe,” says Jennifer Holmgren, LanzaTech CEO. “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 US$10 billion. The acetone and IPA pathways and tools developed will accelerate the development of other new products by closing the carbon cycle for their use in multiple industries.”
The platform could reduce GHG emissions by 160%, according to a LCA.IPA conundrum
While these chemicals (IPA and acetone) are beneficial – serving as the building blocks for thousands of products, including fuels, materials, acrylic glass, fabrics and cosmetics – they are generated from fossil inputs, leading to emissions of climate-warming carbon dioxide into the air.
The secret to the new platform is Clostridium autoethanogenum, or C. auto, a bacterium engineered at LanzaTech that can convert waste carbon selectively into either ethanol, acetone, or IPA. Acetone and IPA are necessary industrial bulk and platform chemicals. For example, acetone is used as a solvent for many plastics and synthetic fibers, thinning polyester resin, cleaning tools and nail polish remover.
IPA is a chemical used in antiseptics, disinfectants, and detergents and can be a pathway to commercial plastics such as polypropylene, used in both the medical and automotive sectors. Both are used in acrylic glass.
IPA also is a widely used disinfectant, serving as the basis for one of the two World Health Organization-recommended sanitizer formulations, which are highly effective against COVID-19.
The collaborators developed a gas fermentation process for carbon-negative production of either acetone or IPA by reprogramming LanzaTech’s commercial ethanol-producing bacterial strain through cutting-edge synthetic biology tools, including combinatorial DNA libraries and cell-free prototyping advanced modeling, and omics.
Strain engineering and optimization 
The researchers say their findings could tap into a US$10 billion market.The scientists relied on a three-pronged approach that comprised pathway refactoring, strain optimization, and process development innovations.
“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,” says Michael Jewett, a professor in Chemical and Biological Engineering in Northwestern’s McCormick School of Engineering and director of the Center of Synthetic Biology.
The process was scaled up to the pilot plant, and LCA results showed significant GHG savings. “Conversion pathways for the production of any biofuel or bioproduct, including acetone and IPA, inevitably involve chemical byproducts that can cause or be the result of major bottlenecks,” remarks ORNL’s Tim Tschaplinski.
“We used advanced proteomics and metabolomics to identify and overcome these bottlenecks for a highly efficient pathway. This approach can be applied to create streamlined processes for other chemicals of interest.”
Circularizing carbon
By proving a scalable and economically viable bulk chemical production, the researchers say they have “set the stage for implementation of a circular economic model in which the carbon from agriculture, industrial and societal waste streams can be recycled into a chemical synthesis value chain to perpetually displace ever-increasing volumes of products made from virgin fossil resources.”
The research joins several carbon capture technology initiatives touted as solutions to GHG emissions. Last year, LanzaTech produced the “world’s first” PET bottle made from carbon capture technology for Switzerland’s largest retail company Migros.
Similarly, Dutch biopolymer pioneer Avantium was awarded €1.78 million (US$2.17 million) in EU grants last year to develop its Volta Technology for producing CO2-based polymers. This platform technology uses electrochemistry to convert CO2 into high-value products and chemical building blocks, which can then be used in polyesters and cosmetics.
By Louis Gore-Langton
