Sandia Studies Enzyme that Breaks Down Lignin Derivatives

Fuel made from plants is much more expensive than petroleum, but one way to decrease the cost would be to sell products made from lignin, the plant waste left over from biofuel production. Sandia scientists, together with researchers from Lawrence Berkeley National Laboratory, have studied LigM, an enzyme that breaks down molecules derived from lignin.

Sphingomonas was discovered to thrive in waste water of a pulp mill. Researchers realized the bacterium's unique enzymatic pathways that enabled it to live on lignin. They then studied the enzymes in these pathways so they could mimic it and use it productively.

The team focused on LigM because it performs a key step in the conversion of lignin derivatives and it is the simplest of the known enzyme systems. LigM was found to break down lignin derivatives, not lignin itself. LigM's function is only one key step in a longer pathway of reactions needed to fully deconstruct lignin. LigM works on a later stage in the process, when smaller lignin fragments already have been converted into a molecule called vanillic acid.

While there is still a need for more research, the team now have a better understanding of the pathway and are developing enzymes to fit their goals.