A research team at the University of California San Diego and materials-science company Algenesis have proven that their algae-based polymer is completely biodegradable.
“When we first created these algae-based polymers about six years ago, our intention was always that it be completely biodegradable,” Robert Pomeroy, a professor of chemistry and biochemistry and an Algenesis co-founder, said on the UC San Diego website on 21 March.
“We had plenty of data to suggest that our material was disappearing in the compost, but this is the first time we’ve measured it at the microparticle level.”
The results were published in a Nature Scientific Reports paper on 12 March.
To test the product’s biodegradability, the team ground it into fine microparticles and conducted a series of tests to check that, when placed in a compost, the material was being digested by microbes, the UC San Diego website said.
In a water flotation test, the team found that after 90-200 days, almost 100% of petroleum-based microplastics were recovered while after 90 days, only 32% of the algae-based microplastics were recovered, showing that more than two-thirds of it had biodegraded. After 200 days, only 3% was recovered indicating that 97% of it had disappeared.
“In this work, particle count and respirometry experiments demonstrated that microplastic particles from a bio-based thermoplastic polyurethane can rapidly biodegrade,” the paper published on 12 March said.
“In contrast, microplastic particles from a widely used commercial thermoplastic, ethyl vinyl acetate, persists in the environment and showed no significant signs of biodegradation over the course of this experiment.”
The research team said that their tests demonstrated that prototype products made from these materials biodegrade under home compost conditions.
Algenesis has partnered with several companies to make products using the plant-based polymers developed at UC San Diego, including Trelleborg for use in coated fabrics and RhinoShield for use in the production of mobile phone cases.
The research was supported by funding from the Department of Energy.
