Scientists from the Lawrence Livermore National Laboratory have utilized innovations in biology and materials-sciences to create what could be an important next-step in environmental management. Using biological components with microscopic 3-D printing technology, the LLNL team has created a flow-through structure that streamlines the conversion of methane to methanol.
The team combined polyethylene glycol diacrylate (or PEGDA) with an enzyme taken from methane-eating bacteria, added a photoinitator, and used projection microstereolithography (a 3-D printing technique) to produce a lattice structure. They then exposed the structure to ultraviolet light to crosslink (or fuse) the polymer chains. The resulting hydrogel was used to produce a liquid solution containing methanol from methane gas. The methanol in the resulting solution was isolated and measured via gas chromatography/mass spectrometry (GC/MS), something we are quite familiar with here at Polymer Solutions Incorporated.
That was a scientific mouthful, but this is really cool stuff! These structures (technically “continuous flow-through bioreactors”, if we’re getting fancy) could potentially be used to convert small, hard to access, or temporary stores of methane gas to its more portable and versatile liquid cousin, methanol. And that could pack a serious punch towards reducing methane emissions from “leaky” sources like landfills and large agricultural operations, which together with the flares and leaks from industrial extraction comprise about 1/3 of current net global warming potential.
Putting a Print on 3-D Printing
While the medical and biomedical fields have readily adopted the use of 3-D printing and bioprinting (combining polymers with cells and their supporting constituents to be used as “ink” in 3-D printing) for medical implants and reconstructions, the team from Lawrence Livermore is the first to have made such an “ink” for the creation of a methane-to-methanol conversion. The bio-“ink” and 3-D printer combo is a match made in laboratory heaven, according to the LLNL research team. 3-D printing “allows fabrication of geometries that are inaccessible by conventional means, the ability to […] minimize the amount of enzyme required for a given volumetric productivity, and the ability to control the location of multiple materials within a structure” (Blanchette et al., 2016). As an added bonus, this particular bioreactor boasts up to 100% enzyme-activity retention—due in part to the structure and area specifications achieved through its projection microstereolithographic (3-D printed) construction—making it ripe for further development and possible use in the energy sector.
Cooperation for Innovation
Though the creation of this bioreactor could mark a major leap forward in environmental management technologies, some obstacles to achieving the methane-recycling dream still remain. For example, the enzyme activity was only stable for a limited time (somewhere around three hours), meaning that continuous use of such bioreactors, as well as the necessary reducing agents, would not be economical. The research team calls upon biologists and material scientists to “work together to optimize biocatalysts through protein engineering and to develop accompanying bioreactor materials” (Blanchette et al., 2016), so that this dream may become a reality.
Photo credit: George Kitrinos, courtesy Lawrence Livermore National Laboratory.
Source: “3-D Printed Polymer Turns Methane to Methanol,” by Anne M. Stark, www.llnl.gov, June 22, 2016.
Source: “New 3-D Printed Polymer can Convert Methane to Methanol,” DOE/Lawrence Livermore National Laboratory, www.sciencedaily.com, June 22, 2016.
Source: “Printable Enzyme-Embedded Materials for Methane to Methanol Conversion,” by Craig D. Blanchette, et al., Nature Communications, June 15, 2016, DOI: 10.1038/ncomms11900.