The UC San Diego researchers who developed algae-based flip-flops and surfboards are at it again. This time they are advancing their brand of renewable and biodegradable materials for use in other products like coated fabrics, patent leather and adhesives, with some foodie flare, too -- flavors and fragrances.
The latest research by Michael Burkart, Stephen Mayfield and Robert Pomeroy -- online in Green Chemistry, a journal of the Royal Society of Chemistry -- outlines their efforts to develop methods for producing microalgae-based polyols -- monomer units for polyurethane polymers -- that can be used to make polyurethane foams with waste oils from algae biomass.
Many researchers consider algae one of the best renewable resources for replacing fossil fuels and battling global warming without impacting food supplies. But unlike vegetable oils, the oil from algae contains small organic contaminants, like photosynthetic pigments and other cofactors that can complicate their use.
The team chose to work with oil from the green microalgae Nannochloropsis salina, a common source of omega-3 fatty acids that are sold as dietary supplements. The leftover oils, more than 70-percent, are typically either thrown away or burned, but the UC San Diego researchers found a better use for them. They developed a process to purify and convert this waste stream into azelaic acid, a building block for flexible polyurethanes. Wanting to "use the whole buffalo," they also converted the co-product heptanoic acid into a food flavoring and fragrance.
"We showed that we could take waste products from algae-based omega-3 oil production and convert those into valuable and renewable polyurethane foams. These have all kinds of commercial applications, from flip-flops and running shoe soles, to mattresses and yoga mats. In addition, we prepared a flavoring molecule from the remaining co-product that is valued at over $500 per kilogram," said Burkart referring to the team's paper, "Co-production of flexible polyurethanes and renewable solvent from a microalgae oil waste stream."
(Source: Agriculture and Food News, ScienceDaily.

Image from the research team’s prior work, showing a student pouring polyurethane into a flip-flop mold. Photo Credit: Erik Jepsen/UC San Diego Publications