Engineered microbe may be key to producing plastic from plants

In Wisconsin, researchers at the Great Lakes Bioenergy Research Center and the Wisconsin Energy Institute have developed a strategy for employing the bacterium N. aromaticivorans to turn lignin into a more valuable commodity. This can help turn woody plants into a replacement for petroleum in the production of fuels, plastics and other chemicals.

The bacterium, which was first isolated while thriving in soil rich in aromatic compounds after contamination by petroleum products, is a biological funnel for the aromatics in lignin. It is unique in that it can digest nearly all of the different pieces of lignin into smaller aromatic hydrocarbons. Their genetic tweaks to the N. aromaticivorans bacteria could jump-start a renewable plastics industry.

In the course of its digestion process, the microbe turns aromatic compounds into 2-pyrone-4,6-dicarboxylic acid — more manageably known as PDC. By removing three genes from their microbe, the researchers turned the intermediate PDC into the end of the line. These engineered bacteria became a funnel into which the different lignin pieces go, and out of which PDC flows.

It would be an attractive plastic alternative — one that would break down naturally in the environment, and wouldn’t leach hormone-mimicking compounds into water.