Study Speeds Transformation of Biofuel Waste into Useful Chemicals

by Jules Bernstein (Phys.Org/Sandia National Laboratories) A Sandia National Laboratories-led team has demonstrated faster, more efficient ways to turn discarded plant matter into chemicals worth billions. The team's findings could help transform the economics of making fuels and other products from domestically grown renewable sources.

Lignin, the tough material left over from biofuel production, contains compounds that can be converted into products like nylon, plastics and drugs. It is one of the main components of plant cell walls, and gives plants structural integrity as well as protection from microbial attacks.

Products made from converted lignin could subsidize biofuel production, making the cost of biofuels more competitive with petroleum. Unfortunately, lignin's toughness also makes it difficult to extract its valuable compounds. Scientists have wrestled for decades with deconstructing it. As a result, lignin often sits unused in giant piles.

Sandia bioengineer Seema Singh and her team have demonstrated two new routes to lignin conversion that combine the advantages of earlier methods while minimizing their drawbacks. The team's recent findings are described in the journal Scientific Reports.

Her team has demonstrated two new techniques that incorporate the speed of a chemical method and the precision of a biological one. In both cases, Singh's team ultimately produced high-value chemicals that currently are derived only from petroleum: muconic acid and pyrogallol.

The team's first new conversion method is a multi-stage process that begins by pre-treating lignin with a weak solution of hydrogen peroxide and water. Intermediary molecules vanillin and syringate result from the treatment.

The second method skips the process of having to break down the lignin altogether. Instead, the team genetically engineered a tobacco plant. As it grows, the plant produces high amounts of intermediate compound protocatechuate, known as PCA. Then, the only steps remaining were to extract that compound and use the engineered E. coli to make the muconic acid. READ MORE Abstract