Date of this Version
United States Patent US 9,598,678 B2
Microbial strains are provided, as are methods of making and using such microbial strains.
Methane is an increasingly important global energy Source, both as the primary component of natural gas and as a biologically produced fuel. Currently, Sweden uses 100% renewable methane (biogas) in place of compressed natural gas (CNG) for transportation fuel, and several European countries are implementing policies to increase their pro portion of biogas transportation fuel. In addition, methane is a valuable chemical for conversion into other higher-order carbon compounds (e.g., methanol, formate, alkanes, ter penes). More than 50% of the world's methane is produced biologically by anaerobic archaea called methanogens, but one significant limitation with industrial scale biological methane production from any type of feedstock is that the rate is relatively slow. Methanosarcina acetivorans is one of a unique group of organisms capable of producing methane from both acetate and methylated compounds, which are common anaerobic fermentation end products. A genetically engineered M. acetivorans strain is described herein that exhibits an increased rate of methane production on methanol and on acetate. Such genetically engineered microorganisms will be an essential tool in the ability to use methanogens as an inexpensive source of methane fuel derived from renewable biomass.