20th Annual Presidential Green Chemistry Challenge Awards highlight biomass- and waste-to-resource technologies

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Courtesy of Bergeson & Campbell, P.C.

On July 13, 2015, the U.S. Environmental Protection Agency (EPA) announced the winners of the 20th Annual Presidential Green Chemistry Challenge Awards (PGCCA) and honored them at a ceremony at the National Academy of Sciences in Washington, D.C. The PGCCAs were created in partnership with the American Chemical Society Green Chemistry Institute® and other members of the chemical community to promote the environmental and economic benefits of green chemistry. The six different categories for the 2015 PGCCAs are: Greener Synthetic Pathways, Greener Reaction Conditions, The DESIGN OF Greener Chemicals, Small Business, Academic, and Specific Environmental Benefit: Climate Change.

The winners of the 2015 PGCCAs include Algenol, for the development of algae to produce fuels; Hybrid Coating Technologies/Nanotech Industries, for the development of a plant-based polyurethane; LanzaTech, for the development of a process that produces fuels and chemicals from waste gas; Soltex, for the development of a reaction process that reduces hazardous chemicals and eliminates water from the production of lubricant and gasoline additives; Renmatix, for the development of a more efficient process to break down plant materials to produce renewable chemicals and fuels; and Professor Eugene Chen from Colorado State University, for developing a waste and metal-free process to turn plant-based materials into fuel and chemicals.

Renmatix seems to have finally cracked the nut that is lignocellulosic biomass. Unlike starch and sugars, plant stalks and wood are quite resistant to rapid biologic action. As a result, most biobased chemical and biofuel producers rely on starch or sugar (e.g., corn starch or sugar cane). The key problem is how to break down quickly lignocellulose into its constituents (lignin, cellulose, and hemicellulose) then break the cellulose and hemicellulose into fermentable sugars. A number of biotechnology companies have been developing enzymes or organisms to deconstruct lignocellulose. Renmatix took a much simpler approach: use the unique properties of water at elevated temperatures to deconstruct lignocellulose into fermentable sugars and lignin in a matter of seconds, instead of days, for biochemical processes. The Renmatix reactor system is robust enough to tolerate a wide variety of lignocellulose, including hardwood, agricultural residue, energy crops, and municipal solid waste, making it ideal for deploying wherever lignocellulosic biomass is plentiful and inexpensive. Renmatix and its partners expect that sugars from the Plantrose® process will significantly reduce the cost of producing chemicals via fermentation from non-food biomass.

LanzaTech has a different approach to biotechnology. Instead of using fermentable sugars, LanzaTech employs extremophiles to convert waste flue gases, rich in carbon dioxide and carbon monoxide, to fuels and chemicals. By employing microbes found on deep sea hydrothermal vents and some creative engineering to ensure robust mixing of the gases and the fermentation broth, LanzaTech can produce ethanol or 2,3-butanediol from the smokestack emissions of industrial facilities. The extremophiles are tolerant of conditions that would be toxic to most industrial fermentation microorganisms, giving LanzaTech a robust and flexible platform from which to produce chemicals and fuels.

Algenol's ethanol producing algae is the first photosynthetic algae technology to win a PGCCA. Algenol has developed a multi-pronged approach to biofuel production by algae. First, the cyanobacteria algae are grown in saltwater -- freshwater is not required -- in specially designed photobioreactors that minimize contamination and water use, and maximize sunlight usage. As the algae grow, they produce ethanol, up to 20 times the per-acre yield of corn-based ethanol. When the algae die, the biomass is converted to a liquid fuel they call 'green crude.' It is somewhat analogous to the natural process that converts fossil biomass to petroleum, but on a much faster time scale. This use of the waste biomass and very efficient processing contribute to a very low carbon footprint.

Soltex is recognized for its development of an alternative to liquid boron trifluoride (BF3) in the production of 'highly reactive' polyisobutylene (HR-PIB). HR-PIB is a key building block for a variety of specialty chemicals, including fuel additives, lubricants, and elastomers and specialty rubbers. The incumbent reaction requires that BF3 be injected continuously into the reactor with high purity isobutylene. Immediately after the reaction, the BF3 must be neutralized and the resulting salt is removed with significant amounts of water. The neutralized BF3 cannot be recycled and is disposed of as waste. Soltex's alternative attaches the BF3 to inorganic beads that are packed in a fixed bed. When the isobutylene passes over the beads, it polymerizes to HR-PIB. Unlike the incumbent process, the Soltex process does not require high purity isobutylene; the HR-PIB comes out in high purity with no residual acid that needs to be neutralized or washed. The process is wastewater-free, saving ten million gallons of water per year for each plant producing polyisobutylene. It also requires much less BF3, in part because the catalyst is more efficient, but also because the catalyst can be reused many times. Less liquid BF3 means fewer opportunities for accidents during manufacturing, transportation, transfer, and use.

Hybrid Coating Technologies and Nanotech Industries have partnered to bring polyurethanes to market without the associated hazards of diisocyanates. These hybrid non-isocyanate polyurethanes (HNIPU) can be used in highly durable polyurethane coatings. Traditional polyurethanes are made by reacting diisocyanates with polyols. Diisocyantes are well known and have well understood hazards, including irritation, lung damage, and occupational asthma (and associated anaphylaxis), and may be carcinogenic. Polyurethanes are so advantageous that they are used despite these hazards, just used with special care to protect workers and end-users. The HNIPU provides the benefits of polyurethanes without the hazards associated with traditional diisocyanates.

Professor Eugene Chen of Colorado State University is recognized for his work on condensation reactions. Condensation reactions are some of the most widely used reactions for chemical production. The catalyst developed by Professor Chen and his group improves the atom efficiency of condensation reactions, that is, it maximizes the atoms that are incorporated into the desired products. High atom efficiency minimizes waste of all kinds simply because more of the starting material becomes product. Professor Chen's group can use a variety of common biobased monomers to make polyester and acrylic polymers. One of the potential polymers is then easily depolymerized back into the starting monomer, bringing significant hope to the circular economy.

Notable in many of these and other recent PGCCAs is that the technologies rely on waste or biomass, rather than non-renewable resources. This reflects the growing success and maturity of companies that rely on renewable materials to make an increasingly diverse set of products.

The Presidential Green Chemistry Challenge has recognized over 100 technologies since its inception in 1996, and each year all of the winning technologies have reduced the use of hazardous chemicals and solvents by over 800 million pounds, saved 21 billion gallons of water, and prevented 7.8 billion pounds of carbon dioxide equivalents from being released into the air.

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