Engineering Methane and Carbon Dioxide Pathways to Turn Renewable Biogas into Higher-Value Chemicals

It is crucial that the United States develop green manufacturing technologies that can produce renewable biobased products at low cost. Organic waste streams are an underutilized source of renewable carbon and energy; efficient use of this resource could reduce our reliance on petroleum. Industrial Microbes is developing a green fermentation technology to convert renewable biogas from organic waste streams into valuable chemicals such as malic acid, 1,4-butanediol, and others. In this grant, Industrial Microbes propose turning biogas into a large market chemical with applications in polymers and high performance plastics. This chemistry will take place inside living bacterial cells using a synthetic enzyme pathway. Cells will convert biogas into chemicals via fermentation, which happens in an aerobic bioreactor located adjacent to the biogas-producing anaerobic digester. Many chemicals are manufactured today using multiple energy-intensive chemical steps which emit significant carbon dioxide. In contrast, Industrial Microbes proposed platform fermentation technology relies on efficient, highly selective enzyme catalysts that can actually consume carbon dioxide. The only byproducts of Industrial Microbes process are water and cells, both of which may be recycled. Some methanotrophic bacteria consume methane, the main component of biogas, in order to grow. Industrial Microbes propose to transfer a metabolic pathway from a methanotroph into a standard industrial bacterial strain, in order to produce chemicals from biogas. Industrial Microbes designs and builds chemical production pathways using modern tools in synthetic biology, metabolic engineering, protein engineering, and directed evolution. Industrial Microbes have selected a bacterial organism that is currently used for industrial scale production of diverse chemicals, but which consumes sugar as a raw material. Industrial Microbes will engineer this bacterial strain to consume methane instead of sugar, and to produce a valuable chemical. Industrial Microbes estimates that this chemical, produced from low-cost biogas, can be manufactured at 50-60% of the cost of current inorganic catalytic methods that start from petroleum. This cost savings is possible because biogas contains low-value carbon which our process can use efficiently. Industrial Microbes estimates carbon efficiency at 60-80%, depending on the composition of the biogas and the specific chemical product. If successful, Industrial Microbes’s process can be expanded to manufacture other chemicals including fumaric acid, lactic acid, butanol, fatty acids, and even fuels. Carbon dioxide pollution is generated during the manufacture of many different products. Industrial Microbes envision a future where advanced materials and fuels are made renewably from everyday household wastes. To get there, Industrial Microbes are developing a biological technology that upgrades waste which would otherwise fill our landfills or pollute our atmosphere.