Advances in technologies such as horizontal drilling and hydraulic fracturing have vastly expanded domestic natural gas reserves (estimate 2,000 trillion ft3 of recoverable gas) and lowered the cost of natural gas relative to oil. Its plentiful supply and low cost are thus encouraging its use instead of oil, sugar, or biomass for the production of fuels and chemicals . Storing and transporting natural gas from remote and offshore sources is expensive relative to its market value, so the gas is often flared or stranded. The World Bank estimates global gas flaring wastes $100 billion and emits 360 million tons of CO2 into the atmosphere yearly, which may significantly contribute to global climate change.
Currently, gas-to-liquid (GTL) technologies that activate methane rely on expensive and inefficient chemical catalysts or on large scale Fischer-Tropsch processes found at refineries, which are not economically feasible at small scale. A biological low-capital approach for the efficient and sustainable activation of methane gas comes from nature in the form of methanotrophic bacteria that feed on methane as their sole source of carbon and energy.These organisms selectively oxidize methane to methanol using metalloenzymes called methane monooxygenases (MMOs) and do so under ambient conditions in a environmentally friendly manner.
In a 2010, Balasubramanian et. al. from the Rosenzweig lab at Northwestern University generated a first-generation construct of MMO (termed spmoB) that could be expressed insolubly in E. coli while still maintaining a small percentage of its natural methane-oxidation ability after protein refolding. In 2013, we established a collaborative project between the Rosenzweig and Mayo laboratories and Protabit, LLC. to engineer spmoB. Our goals are to apply CPD along with high throughput screening technologies to engineer a stable, soluble and active spmoB variant, which would ultimately serve as the enabling step in a bio-GTL pathway for creating transportation fuels and high-value chemicals.
Sarah Gillespie - graduate student
Jingzhou Wang - graduate student
Rosenzweig Lab, Northwestern University