If you hang out with chemists very often, you’re bound to hear one of their favorite witty wisecracks about lignin at some point: “You can make absolutely anything out of lignin … except money.”
This full of potential yet still scorned complex polymer, lignin, is nature’s glue filling up spaces in plant cell walls, helping move water and giving plants rigidity. Lignin is what allows trees and plants to grow tall and accounts for about a quarter of all of the plant matter. Cellulose, hemicellulose, and lignin comprise the vast majority of most plants considered to be good biomass feedstock candidates for conversion to biofuels, biopower, biochemicals or bioproducts. Lignin is the second most abundant polymer on Earth, right behind cellulose, hence the generic characterization “lignocellulose” for most all biomass-derived feedstocks.
The reference to lignin’s doom to the realm of the unprofitable is in in part because most all of the lignin historically available at an industrial scale has been a pretty nasty leftover mess resulting from the kraft process (sulfate pulping) used in manufacturing paper. The harsh chemicals involved in traditional pulping are largely to blame for lignin’s bad rap, limiting options for further uses other than harvesting the energy content as boiler fuel. While lignin has about the same energy content as coal, there’s so much untapped potential value in this hopeful superstar of the plant world.
Modern biorefineries focused on producing advanced biofuels like cellulosic ethanol are changing lignin’s destiny. If there is such a thing as “pretty” lignin, we’re now seeing it for the first time—or at least with fresh eyes. Compared to kraft lignin, milder biorefining processes may yield enormous quantities of high value lignin-derived products from plastics to specialty chemicals to carbon fiber and most anything in between.
A highly efficient (and profitable) sausage manufacturer is said to use every part of the pig but the squeal. Similarly, a highly efficient and profitable biorefinery needs to extract the highest value possible from every constituent component of the lignocellulosic biomass feeding the process, including the lignin.
While there’s reason to be optimistic about lignin’s future as a staple in our manufacturing arsenal, there’s also reason to temper that enthusiasm with a dose of reality. Despite rapid progress and promising results, we still have a long bridge to build between successful lab scale lignin science and scalable, cost competitive products on the market. As the first wave of commercial-scale advanced biorefineries is coming online now, they are rightly focused on maximizing the fuel value of the lignocellulosic feedstock. But ultimately, both the biomass and the fuel products are commodities, providing economic incentives for focusing on the profitability potential of lignin.
As the country’s leading experts in developing, establishing, and operating efficient and reliable supply chains for lignocellulosic biomass—particularly from purpose grown energy crops—Genera Energy will continue to follow closely the quest for chemistry’s elusive zenith: money from lignin.
By Kelly Tiller, President and CEO
