As technology improves and we hunt down and manage to find new sources of crude oil and natural gas — the quantity of natural gas that we waste also increases. In many operations, methane is vented or flared and has a much lower market value. This is partly because of the difficulty in storing and transporting methane — especially when compared with other hydrocarbons.
But now — thanks to Mother nature combined with the advances in 3D printing — we might soon have a method that can cheaply and efficiently reduce the amount of methane we waste. The work has been reported in the journal Nature Communications.
The ideal state of affairs is to convert the methane into a form that can easily be captured such as liquid hydrocarbons — and in many situations this is what happens. But the equipment required to carry out such a process requires significant capital investment. It’s also relatively inefficient with a low conversion rate of methane to liquid hydrocarbons— subsequently the process is only carried out where economies-of-scale warrant the investment.
Consequently, a method to convert methane to a product that is easily stored and transported in remote or ‘stranded’ situations (sources that are small, temporary or not close to a pipeline) is needed. And this is what the team from the Lawrence Livermore National Laboratory, California has developed using biology and 3D printing technology.
Methanotrophs and 3D printed polymers
Methanotrophs are prokaryotes that use methane as a source of carbon and energy. The methane is converted to methanol by an enzyme in the methanotroph called methane monooxygenase or MMO. The amazing thing about the enzyme is that it is the only known true catalyst able to convert methane to methanol under ambient conditions.
Methanotrophs are found in soils and are common in areas where methane is produced such as landfill sites. There, they play a role in reducing the amount of methane being released into the environment — playing a significant role in bioremediation processes and in reducing the amount of greenhouse gas released into the atmosphere.
The team isolated the enzymes from the organisms — as the enzymes alone offer greater flexibility. To use the enzymes, the team had to find a method of supporting and fixing the enzymes so the methane could be passed over them — a substrate that wouldn’t stop them working and could be shaped.
The team found that embedding the MMO in a polymer of polyethylene glycol diacrylate (PEGDA) which is simple to use and polymerize. The team showed that the MMO/PEGDA substrate was an efficient ‘bioreactor’ converting methane to methanol as measured by GC. The team suggest that with further work, the biopolymer substrate could be used to manufacture simple reactors that could help reduce the amount of methane wasted by converting it into a useful product. Improved GC techniques to measure alcohols and other polar solvents are discussed in the article, Better with Both: Leveraging Polar Selectivity and Polar Inertness using SLB®-IL (i-series) Capillary GC Columns.