Methanotrophic bacteria oxidize methane as their sole carbon source to support cellular metabolism and growth. Intrexon developed a suite of tools enabling the rapid manipulation of methanotrophic organisms—e.g., gene knock in/out, direct transformation/electroporation, and plasmid-based expression system—to incorporate complex metabolic pathways into methanotrophs for the production of industrial products.

With new genetic circuitry, the methanotroph upgrades carbon from its natural food source, methane (C₁), to more valuable end products—e.g., isobutanol (C₄) and farnesene (C₁₅). Beyond these two products, Intrexon’s proprietary carbon upgrading platform via the methanotroph has the potential to produce other valuable chemicals as well.

Additionally, through a substantial yield advantage of the methanotroph over other microbes, Intrexon’s bioconversion platform has a favorable economic profile that, based on current targets, will allow even small scale demonstration plants to achieve profitability within the first year of production, the company said.

At present, Intrexon has two different engineered microbial hosts, both operating in laboratory-scale bioreactors: one that converts methane into isobutanol, and one that converts methane to farnesene.

Both engineered methanotrophs present a unique series of challenges for commercial scale up, noted Intrexon in a presentation at the 2015 BIO World Congress in July. Expressing a heterologous pathway for product generation places additional metabolic burdens on the cell, as carbon is diverted from primary to exogenous metabolic pathways.

Intrexon’s fermentation bioreactor protocol supports growth of an isobutanol producing engineered methanotroph at industrially relevant cell densities; the company’s focus in now on scaling. In addition, Intrexon developed a high-throughput platform for the systematic testing and iterative optimization of media composition and strain performance while also facilitating rapid design and testing of new pathways for improved isobutanol production from engineered strains.

Under the terms of the agreement with Dominion, IEP will be required to meet specific development milestones prior to initiation of certain commercialization activities, which are subject to board approval by both parties.

Dominion will be the exclusive partner to construct, own, operate, and maintain the production facilities in the Marcellus and Utica Shale Basins located in eastern North America via potential long-term services agreements with IEP. Within this geographic region, the collaboration plans to build natural gas bioconversion facilities leading to the creation of job opportunities and generation of local and state tax revenue.

Conversion of methane to isobutanol provides economic and environmental advantages upon which the collaboration will look to build. In comparison to other gasoline substitutes, isobutanol offers cleaner burning combustion with less corrosion, holds more of gasoline's energy content allowing longer travel, is cheaper to blend with gas, and its compatibility with the current petroleum infrastructure offers a dramatic improvement in efficient transport of the fuel itself. These positive attributes are driving investment in butanol plants which may reach $6 billion by 2020 according to Bloomberg New Energy Finance.

Dominion is one of the largest US producers and transporters of energy, with a portfolio of approximately 24,600 megawatts of generation, 12,200 miles of natural gas transmission, gathering and storage pipeline, and 6,455 miles of electric transmission lines. Dominion operates one of the US’ largest natural gas storage systems with 928 billion cubic feet of storage capacity and serves utility and retail energy customers in 13 states.

Resources

• US Patent Application Nº 20140273128A1: Biological Conversion of Multi-Carbon Compounds from Methane