Bill Scanlon, NREL
January 21, 2014 | 8 Comments
Scientists from NREL, UW, and LanzaTech have already shown at laboratory scale that the unique microbe growing in a simple mineral medium supplemented with a salt and carbonate buffer can double in three hours—twice as fast as other methanotrophs. Even with the faster growth, the lipid content comes in at an impressive 17 to 22 percent.
NREL's first major challenge was to demonstrate that the process can be done safely. In NREL's Integrated Biorefinery Research Facility, microbes consume the methane fed carefully into a fermenter, under the watchful eye of NREL Scientist Qiang Fei. "It's all about safety," Fei said, demonstrating how controls can combine methane and air in a safe way. He worked on the process for months, and in December, the continuous-feed system passed a safe work permit (SWP) protocol. That marks a big step on the road to getting commercial-scale fermenters to well sites.
UW researchers are focusing on genetically modifying the microbes to both increase the amount of membrane lipids and get the microorganism to produce non-phosphorous-based lipids that are more readily converted to fuels. At the same time, the United Kingdom-based Johnson Matthey team is working to convert the phospholipids into diesel fuel. Combining the super microbe with the best methane oxidation machinery at the fracking wells could result in a bumper harvest of lipids and create conditions that will yield even higher liquid fuel outputs.
New Zealand-based LanzaTech, a pioneer in waste-to-fuels technology, has signed on to take the bench-scale plan to the commercial level if it is successful.
NREL in Charge of Fermentation; Will Analyze Economic Potential
NREL is in charge of fermentation to demonstrate the productivity of the microbes in batch cultures of both the native organism and the genetically altered varieties. NREL will also extract the lipids from the organisms and analyze the economic potential of the plan. Pienkos and his colleagues at NREL have been establishing a safe operating system to ensure there won't be any incidents with the experimental plan.
"We developed a great relationship with NREL's Environment, Health, and Safety Office, with all participants committed to both safety and the success of the project. We spent six months taking baby steps to grow the culture, but we've turned the corner," Pienkos said. "We're about to see a huge spike in progress. This is also serving as a new model for the research we do in the National Bioenergy Center. We are working with new feedstocks and producing new target molecules. We are absolutely committed to making sure that all the safety pieces are in place before we get started."
Challenges remain. Using microbes to convert methane depends on the mass transfer of gaseous oxygen and methane, neither of which are very soluble in water. In addition, the heat generated by the rapid growth must be removed.
But interest in the process is high. An Energy Department Bioenergy Technologies Office workshop in Chicago on turning natural gas into liquids drew a large crowd of important industry players. In addition, ARPA-E has recently awarded winners in its REMOTE (Reducing Emissions using Methanotrophic Organisms for Transportation Energy) solicitation to identify additional technologies to convert methane to fuels.
Potential to Disrupt the Transportation Fuel Paradigm
This countertop experiment — which is feeding methane into a fermenter that contains microbes capable of consuming the methane — is a prototype of the fermenters that in the future may digest methane at many of the 600,000 fracking wells in the United States. Photo by Dennis Schroeder, NREL
In its application to ARPA-E, the research team asserted that the process will simultaneously capture the energy lost by the stranded natural gas, provide a new source for liquid hydrocarbons, and mitigate greenhouse gas emissions — and the process will provide new jobs and new production capacity, while disrupting the current liquid fuel paradigm. That's because the Bio-GTL diesel product can use the existing pipelines at extraction sites to travel to refiners where it will undergo processing. It could prove useful for petrochemicals, too.
One more potentially transformative benefit: the single-cell protein produced as a byproduct has been explored for more than 20 years as a source of nutrition for both humans and animals.
Save trillions of tons of greenhouse gas; produce liquid diesel cheaply and safely; create a source of nutrition for livestock and people.
Not bad for an organism too small to see.