Researchers develop microalgae-based polyols for polyurethane polymers


UC San Diego researchers develop methods for producing microalgae-based polyols for polyurethane polymers. The polymers can then be used to make polyurethane foams.

Converting Microalgae Oils into Azelaic Acid

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. They also converted the co-product heptanoic acid into 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.,” said Michael Burkart.

To start the work, the research team first found a scalable, cost-effective pathway to improve the purity of algae oil using simple physical methods along with saponification. This is a process by which oils react with sodium or potassium hydroxide to produce glycerol and a fatty acid salt, or soap.

In addition to the fatty acids, the team identified multiple contaminants in the waste oil. Microalgae contain a variety of metabolic components that are insoluble in water but freely soluble in the algae oil when extracted. The presence of these pigments inhibits downstream reaction efficiency, therefore their removal is a key process in the production of renewable chemicals from algae oil.

Scalable Process Can be Performed on Multiple Algal Species Oils According to the scientists, their scalable process can be performed on oils from multiple algal species, to produce valuable monomers—molecules that take part in a chain reaction to form polymers—for a highly sustainable source of bio-based plastics. The study included an exploration of the economic value of the team’s methodology. Researchers chose the N. salina as a strain for growing algae in large scale because of its established high production of eicosapentaenoic acid (EPA), a valuable omega-3 oil, and the ability of scientists to grow the strain for high biomass content. “We are already working with major shoe companies to turn these into commercial products that people will want to buy. We are finding that consumers are concerned about all of the petroleum-based plastic waste we are generating as a society, and our team is rapidly developing solutions for future products,” added Burkart, 20 May 2020