Researchers at North Carolina State University have developed a simple and effective technique for removing lignin – nature’s way of protecting plant cell walls – from the plant material used to make biofuels.
This discovery may bring down the cost of biofuel production in a big way.
Lignin is difficult to break down or remove from plant materials called ‘biomass’ – such as the non-edible parts of the corn plant.
“However, lignin needs to be extracted in order to reach the energy-rich cellulose that is used to make biofuels,” said Ezinne Achinivu, a PhD student in chemical and biomolecular engineering at NC State University.
The researchers began by making a number of liquid salts called ‘protic ionic liquids’ or PILs.
These PILs are prepared by mixing together acetic acid (vinegar) and a base (a chemical class of materials called amines), said the study published in the journal Green Chemistry.
As part of the pre-treatment process, one of the PILs is mixed with biomass and then heated and stirred.
The lignin dissolves into the PIL, leaving the cellulose behind as a solid.
The cellulose, which is now much easier to process, is then easily filtered from the mixture for use in the next biofuel production steps, added the study.
“The lignin is also valuable because it can be used to manufacture polymers or other chemical products which could supplement the cost of running the biofuel production facility,” said Achinivu.
“We need to scale up this PIL-based technique which would not only be more energy efficient but also less expensive than existing biomass techniques for removing lignin,” he added.
The researchers are currently working to apply the technique to wood and other biomass feedstock materials.