Accidental discovery bubbles with promise for safer hydrogen storage

David Johnson was a doctoral candidate in 2007 working on lab experiments for his dissertation in molecular biology at NMSU when he unexpectedly identified a biopolymer that could result in safer hydrogen storage.

Johnson, who now has his doctorate and is working at the NMSU Institute for Energy and Environment, was working on a National Science Foundation-funded grant to find a unique hydrogen-producing microbial community when he noticed some unusual bubbles forming in the reactor.

The bright white bubbles were forming a biopolymer that NMSU biology researcher and professor Geoffrey Smith didn't recognize.

This biopolymer was also capturing and storing hydrogen as the gas was being produced. With a tight molecular structure that made it impermeable to hydrogen, the biopolymer also demonstrated elastomeric properties that are similar to natural rubber.

Smith screened the polymer against thousands of known compounds, but it wasn't clear what organisms produced the polymer.

"We then sampled the polymer bubble with a gas-tight syringe and injected samples into a gas chromatograph," Smith said. "We found hydrogen gas, along with some other gases, in the bubbles."

Hydrogen, the smallest molecule in the universe, is hard to contain because of its size and corrosive properties. Expensive PVC piping and stainless steel materials are currently being used for hydrogen storage and transport, but hydrogen diffusion erodes metals over time, causing them to become brittle. This leads to structural failures in storage and transporting piping.

The polymer's properties encouraged Smith to think of potential applications.

In 2009, through NMSU's Launch proof-of-concept program at Arrowhead Center, Smith connected with Michael Townsand, a master's biology lab researcher. Townsand reviewed Johnson's dissertation notes to try and replicate the serendipitous discovery.

Townsand proved that the polymer producer was a yeast, and was able to replicate the biopolymer production after simplifying the production feeding the yeast sugar under specific temperature and pH conditions in a process that came to be termed "biohydrogenesis."

"The enzymes inside of the cell are the essence of biotechnology," Smith said, "which is harnessing natural processes that synthesize and export the polymer outside the cell."

To protect the technology, Smith turned to Arrowhead Center's Office of Intellectual Property and Technology Transfer, and has applied for a patent for the polymer, now known as Hydromer. Arrowhead's director of intellectual property and technology transfer, Terry Lombard, is working with Smith on commercializing Hydromer as a coating material will allow for low maintenance costs and high durability for hydrogen storage.

"Dr. Smith's Hydromer technology is expected to provide a safe hydrogen storage method that may overcome some of the existing concerns with hydrogen transport," Lombard said, "and move the trend and experiments with hydrogen-fueled vehicles quicker to commercialization and the marketplace."

With funding from the New Mexico Small Business Assistance Program, Sandia National Laboratories is working to provide testing and validation of Hydromer's heat resistance, tensile strength and hydrogen permeability, along with other characteristics critical for safe hydrogen transport and storage, and for hydrogen-fueled vehicles.

"The Hydromer project is a great example of collaboration resulting in a more vibrant, innovative and entrepreneurial landscape in New Mexico," said Griselda Martinez, NMSBA's program manager for Arrowhead. "It is intellectual property created by a faculty member at NMSU, who is working with Arrowhead Center on licensing and funding opportunities and receiving technical support through the NMSBA program at Sandia."