LLNL Researchers Use 3D Printing to Turn Methane to Methanol

Scientists of the Lawrence Livermore National Laboratory combined 3D printing technology with biology to create a reactor that can produce methanol from methane at room temperature and pressure. The study titled “Printable enzyme-embedded materials for methane to methanol conversion” was published in Nature Communications.

By removing enzymes from methanotrophs, a bacteria that eats methane, and mixing it with polymers, researchers were able to 3D print or mould them into innovative reactors. The findings could lead to more efficient conversion of methane to energy production.

LLNL chemist and project lead Sarah Baker explains: “Remarkably, the enzymes retain up to 100 percent activity in the polymer. The printed enzyme-embedded polymer is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas-liquid reactions.”

Methan is the main component of natural gas and its abundance on Earth makes it an attractive fuel. Methane emissions are said to contribute about one third of current net global warming potential, emitted by natural sources and human activities such as leakage from natural gas systems, the raising of livestock as well as landfills. Current technologies used to convert methane to other products operate at high temperature and pressure and require a large number of unit operations, thus the efficiency is very low.

The only catalyst known for the conversion of methane to methanol under ambient conditions with high efficiency is the enzyme methane monooxygenase (MMO). This reaction can be carried out by methanotrophs containing the enzyme. As this however requires energy for upkeep of the organism, the LLNL research team separated the enzymes from the organism and used them directly. These isolated enzymes react highly controlled with higher conversion efficiency and greater flexibility at ambient conditions. The 3D printed, enzyme-embedded polymer allows for reuse over many cycles and can be used in higher concentrations.

“Up to now, most industrial bioreactors are stirred tanks, which are inefficient for gas-liquid reactions,” explained Joshuah Stolaroff, an environmental scientist on the team. “The concept of printing enzymes into a robust polymer structure opens the door for new kinds of reactors with much higher throughput and lower energy use.”