Another Use for Lignin

Research Collaboration Demonstrates an Additional Way to Replace Petrochemicals With a Renewable Alternative

In a lab at Michigan State University (MSU), researchers are trying to revolutionize the wood adhesives industry using an agricultural co- product supplied by the team at POET’s Project LIBERTY, POET-DSM Advanced Biofuels’ commercial scale cellulosic biofuels facility in Emmetsburg, Iowa. The joint POET- DSM venture uses biowaste like corn cobs, leaves and husk to produce cellulosic ethanol.

What MSU researcher and assistant professor Dr. Mojgan Nejad’s team has found is that lignin — organic material that is left over from biofuel production — can completely replace petroleum-based phenol, a toxic ingredient in wood adhesives. In the last 30 or so years of published work on replacing phenol with lignin, Nejad’s research was the first to prove the viability of 100 percent replacement of phenol with lignin.

Using a bio-based alternative instead of a toxic, chemical-based one offers the potential to bring not only health benefits for construction workers and consumers at large but also cost savings for the adhesive industry. The collaboration has been successful, group members from POET and MSU say, in part because of their shared vision to replace petrochemicals with green, renewable alternatives. The POET/MSU collaboration recently won the 2018 Small Business Innovation Award from the Adhesive and Sealant Council for the group’s efforts.

Lignin has long been considered to have little marketable value. Lignin, which acts as natural glue in plant cell walls, is the second-most abundant natural polymer in the world, behind only cellulose. As part of their “use every byproduct” philosophy, the team at POET burns the dry lignin to create steam that provides heat and power to Project LIBERTY.

When Nejad analyzed POET lignin isolated from corn stover, she found that POET lignin is a suitable lignin to replace petroleum-based phenol.

“Our goal is to convince adhesive producers that they can formulate a bio-based adhesive with similar performance as a petroleum-based adhesive using lignin,” Nejad says. “I had wanted to be a chemistry professor since I was 9 years old, and now that I have my dream job, I am passionate to see that our work can make a positive change in the world. This work has a great potential to improve the health of industry and construction workers and also the general public by reducing their exposure to phenol and formaldehyde. We found that the developed lignin-based adhesive contains 50 percent less formaldehyde than the petroleum-based phenolic adhesive that is currently available on the market.

Phenolic adhesive, in fact, is the most common adhesive in the production of exterior-grade wood products (plywood, oriented strand boards and laminated veneer lumber), and had a market value of $11 billion in 2016, a number expected to grow to $16 billion by 2022, according to Stratistics MRC, a global market research company.

The switch could be a direct savings for the adhesive industry, since the phenol is petroleum-based and its cost fluctuates with the price of oil, unlike lignin that is produced from agricultural waste produced in the United States.

This type of project focused on sustainability seemed like a great fit for POET and Nejad to again work together. They had started working together six years earlier, when Nejad was doing her postdoctoral research at the University of Toronto.

When Nejad asked for samples from POET, the company shipped lignin in various forms. The lignin from Project LIBERTY, turned out to be different than other lignins. It also turned out to be the best candidate for phenol replacement.

“The collaboration with Mojgan and Michigan State has been great for everyone involved,” says Tyler Jordison, a POET research scientist (and a Michigan State grad). “She mentors us on lignin and its composition and capabilities, and we have shown her how it may be possible to produce these results on a large scale. Her lab results of replacing phenols with lignin have been surprisingly positive.” “We were hoping to get maybe 60 percent of phenol with lignin,” says Nejad. She was at a conference when her PhD student (Isal Kalami) called and was excited to report, after continuing to increase the mixture, “the adhesive developed by replacing 100 percent of phenol with lignin, had excellent water resistance and did not dissolve in water after 24 hours of a water immersion test.” Nejad and her team then began to work on optimizing the resin and adhesive formulations, and received even more promising results. With the new mixture, the amount of formaldehyde — which is very toxic, and its emission is always a concern with woods products — was decreased by 50 percent.

Various tests proved the wet and dry adhesion performance of developed lignin-based glue were similar to phenol-based glue.

“This was very exciting,” says Nejad. “We need more research to also replace 100 percent of formaldehyde with a bio-based, nontoxic raw material, but we now have a formulation that has very similar performance to the petrochemical-based adhesive. We got a perfect result, and are now happy to see that some adhesive producers are seriously looking at replacing phenol with lignin.”

For POET Bioproducts Research Director Steve Bly, the lignin research shows promise, but more important is the long-term, relationships by these collaborations.

“The best part of these collaborations is that they benefit both POET and the university researchers,” says Bly, now in his tenth year at POET. “We’re involved in a number of these collaborations, and the university professors extend our reach from a research perspective. Mojgan is a well-respected expert in lignin utilization and her knowledge in this area helps to accelerate our research efforts. We give them feedback, and show them real-world applications from a commercial standpoint. Even hundreds of miles apart, we’re working together for the same goal: replacing toxic petroleum- based compounds with something that’s safe and grows naturally.”

Margaret Slupska, Lignocellulosic Research Director at POET, agrees. “Lignin is a really fascinating compound when you think about how it is structured and how abundant it is in nature,” she says. “We believe in this collaboration with Mojgan. We believe in this collaboration with Michigan State. And finding a use for a biochemical as an alternative compound to a petrochemical completely aligns with the mission and vision of POET.”

And for Mojgan Nejad, that big- picture plan of replacing toxic ingredients with safe alternatives is a lifelong passion.

“We can really do this,” she says. “We can change an entire industry for the better. We can make the whole world safer. Everything that is made of petrochemicals we could someday replace with plant-based materials. Think what a difference that would make.”



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