An Optimized Biocatalyst for Efficient Conversion of CH4 and CO2 into Bioproducts

Significant amount of methane from natural gas/crude oil extraction and anthropogenic sources are either flared or vented because it is a cheaper option compared to the capture and use by the existing technologies and/or infrastructures. Methane is an energy-dense molecule (55 MJ/kg) and thus provides opportunities for its conversion into valuable bioproducts using bio-based technology. The goal of this project is to develop a bio-based technology to capture methane, CO2 and other trace gases such as H2S and NH3 towards production of high value products useful in animal and human nutrition. During the Phase I research, we successfully metabolically engineered a methanotroph to convert methane, CO2, H2S and NH into a high value product. Several genetic modifications were carried out which decreased the flux of carbon towards fermentative waste/storage products, eliminated competing pathways, and improved the carbon flux towards the targeted product. The optimized biocatalyst produces the targeted bioproduct at a significantly higher titer and rate. The objective of the Phase II project is to complete the development of prototype biocatalyst by metabolic engineering of the remaining bottlenecks identified during the Phase I research, establish an economical extraction process from fermentation broth, and optimize the volumetric productivity in a bioreactor at lab scale utilizing actual biogas. The proposed technology provides an operationally safe process, simplifies the overall process resulting in less capital and operational expenditures, and utilizes methane and CO2 as feedstocks. It also reduces the complexity of multiproduct intermediates and handling of toxic intermediates during production of the targeted products compared to the existing methods. Furthermore, the proposed technology can be profitably operated at small scale and would help capture stranded natural gas and develop small scale biogas production facilities. The anticipated result of this SBIR Phase II research project is establishment of a prototype integrated bioprocess that will convert biogas (and stranded natural gas) into high value products at a competitive cost.