US lab produces ethylene through photosynthesis

After the culture reaches maximum growth, it’s possible that it could keep producing for months at a time, said Rich Bolin, who is a member of NREL’s partnerships group. The ethylene gas it produces naturally leaves the organism, spurring the organism to keep producing more.

The ethylene would be produced in an enclosed photobioreactor containing seawater enriched with nitrogen and phosphorous. The ethylene gas would rise and be captured from the reactor’s head space. It could then undergo further processing, including a catalytic polymer process to produce fuels and chemicals. The continuous production system improves the energy conversion efficiency and reduces the operational cost.

NREL is initiating discussions with potential industry partners to help move the process to commercial scale. Interested companies include those in the business of producing ethylene or - transportation fuels, as well as firms that build photobioreactors.

“Separations in biotechnology are complicated and costly,” said Jim Brainard, director of NREL’s Biosciences Center. “The nice thing about this system is that it is a gas that just separates from the culture media and rises to the head space. That’s a huge advantage over having to destroy the valuable culture that is taking carbon dioxide and light and water to make your product. It’s much easier than a liquid-liquid separation like in ethanol.”

NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by the Alliance for Sustainable Energy, LLC.

National Renewable Energy Laboratory (NREL)