In Love with Lignin
While Martin Lawoko was in primary school in Uganda his father was in exile, one of a lucky few to escape the infamous killing floors and blood soaked cells of Uganda’s “State Research Center” at Nakasero. In a country where chaos and brutality surrounded much of his young life, Martin found order and magic in organic chemistry.
Martin clearly remembers his first chemistry class. His teacher entered the classroom holding up a glittering test tube. According to Martin, “he turned it around and it changed color. He turned it around again and again it changed color.” That was the moment Martin fell for chemistry. “I was transfixed by how molecules were attracted to each other.” Ordinarily that moment might give birth to a rarified scientist but Martin is clearly grounded in the physical world: “Life is organic chemistry. It’s what we are made of.”
Safely in Sweden to join his father, he became a chemical engineer and followed that degree with a Masters at the Swedish Pulp and Paper Institute and a PhD at the Royal Institute of Technology. Attaching himself to the pulp and paper industry was almost a compulsory course for Martin. “In Sweden,” he notes, “pulp and paper is one of the largest industries and 80-90 % of student chemical engineers in my class ended up working in pulp and paper mills.”
While Martin could have followed a well worn path into Sweden’s mills, he found his way instead to the University of Maine, first as a post doctoral researcher and then as an analytical chemist. UMaine’s Dr. Adriaan VanHeiningen (known for his pioneering work to extract wood fibers for bio-based fuels) met Martin at a thesis defense in Sweden, “expressing interest in some of the work I had published about lignin carbohydrate bonds,” explained Martin. “We kept in close contact for a year and before I graduated, I expressed my interest in doing postdoctoral work with his group.” Martin’s ability ‘to see’ the organic world differently is what makes him valuable to the university’s work to replace carbon-based fossil fuels and products with wood based alternatives.
As an analytical chemist for UMaine’s Forest Bioproducts Research Institute, Martin’s job is to design and conduct experimental work on chemical, thermal and physical properties of biomass, wood fibers, paper or other materials as well as maintain and operate a variety of laboratory facilities. He is now part of a broad array of campus researchers and scientists creating energy solutions and fossil fuel replacement products that signal the next generation of advances in wood technology.
FBRI’s Science Director, Dr. Stephen Shaler, explains the promise of wood. “Advances in science, coupled with better understanding of the ecosystem, the biology of tree growth and the chemistry of breaking wood down, allow us to approach forest biorefining (creating many wood products at one location) more efficiently than we have in the past. Almost anything that is now made from petroleum, can now also be made from wood.”
Martin’s research revealed a novel method for “seeing” bonds and linkages in wood. He created a different analytical model that more fully analyzed cell wall structures and linkages so wood fibers might be successfully separated and then later recombined as new products, new products that do not contain petroleum.
Robert G. Wagner, professor of forestry at the University of Maine and part of the FBRI research team, is clear about the future of wood bioproducts. “The time will come, in two or three decades, when we will look at the days of only sawing boards and making paper as the Dark Ages,” he says. “The chemical versatility of wood is so great, we will cringe at the idea we were once wasting it.”
Wasting wood is just what Martin wants to avoid and he most wants to create better uses for lignin. “I love lignin! Everybody burns it. We might as well make some value of it; there’s more value in extracting it.”
There’s a lot to love about lignin, one of three essential fibers that make wood…wood. Lignin makes up (in our entire world) about 30% of all non-fossil organic carbon and the even better news is that its strength and binding properties are equal to petroleum based products. Martin says his research works to free lignin and “separate it out as a fiber element able to do its own work. (It usually works to hold cellulose and hemicellulose together.) It has the potential to strengthen cars and airplanes with a fraction of the weight of conventional reinforcement materials.”
Wood is composed of three kinds of essential fibers: cellulose, hemicellulose, and lignin. Imagine the makeup of wood as many, many glued together toilet paper rolls (one of the most popular wood products all by itself). The “rolls” are the various fibers that are bonded together as wood (50% cellulose, 25% hemicellulose and approximately 25% lignin). Lignin is a three dimensional polymer that holds wood together. (A polymer is simply a collection of molecules.) Imagine a three dimensional chicken wire fence and it is easier to see why lignin polymers “hold” other wood fibers together. Forcing this lignin fence (that also acts like glue) to unstick and release itself from other fibers is the secret to separating wood elements so each can be directed to many new sources of fuels, energy, plastics, binders, insulators, coatings and other wood based products.
Martin’s research helps chemists to “see” that lignin is linked (essentially stuck) in two different ways to the hemicellulose in wood. Hemicellulose wood fibers contain both xylan and glucomannan and each of these elements has a different bonding relationship with lignin. Martin explains that since “xylan is more linear and consists of more easily breakable bonds, the lignin is easier to extract and divert to the creation of value added wood products. The key to really using wood as a renewable resource…a substitute for fossil fuel… is how we break the fiber bonds to release the potential of wood’s core (literally) elements.” Martin’s research locates the bonds that more easily break apart the glued toilet paper rolls of wood fiber.
As wood is released into its various elements the cellulose still flows into the production of pulp and paper; the hemicellulose, extracted and fermented, becomes biofuels and energy. Lignin (if Martin has his way) will take its rightful place as a wood fiber with limitless potential as an insulator, an adhesive binder in materials and even a dispersant preventing clumping and settling that degrades the value of cement, dyes, clays and numerous other mixtures used every day by consumers as well as industry. Asked to wave a magic wand over the potential of lignin, Martin smiles and says he “expects it to become a fuel that runs cars someday.”
When Martin explains that he “loves lignin” his eyes are bright and animated, still the eyes of a boy who fell for a world where molecules are attracted to each just as he was attracted to chemistry. If “life is organic chemistry” as Martin Lawoko claims, then the curious boy, the Ugandan refugee, and the analytical chemist in Martin are in an ideal position to take that hard won faith in the natural world and research us some bright new solutions for our future.