According to popular science, plastic waste and microplastics are almost everywhere in the world. These items can be found from the sky to the sea, as many different plastics enter the waterways and take hundreds of years to rot.
Compostable plastics such as corn-based plastic cups and straws are often advertised as suitable alternatives. The Colombian Climate School said plastics could become landfills without proper composting equipment.
How biodegradation helps solve plastic pollution
Ting Shuo, a professor of materials science, engineering, and chemistry at the University of California, Berkeley, and her team use a new polymer coating on enzymes that can be incorporated into bioplastics to make it easy to make new compost at home. A report that explains how to do this.
They have published their study, “Almost Complete Depolymerization of Polyesters with Enzyme Nanoscale Dispersants,” in the journal Nature.
“So I always thought biology taught us everything … we need to adapt to it,” Shaw told Popular Science.
The enzyme, coiled around a random heteropolymer, is spun into fresh plastic that is easily biodegradable during manufacturing. The enzyme is encapsulated in these polymers, such as RHP, so it does not lose its value when separated. According to Xu, previous efforts to bury the enzyme without the use of RHP resulted in large lumps of rubber that were “feta cheese-like.”
As the plastic warms, the polymer jacket bursts, and the enzymes begin to “eat” the plastic. This analysis tested this technique using two polyester polymers used in biodegradable plastics: polycaprolactone and polylactic acid. The addition of the enzyme encapsulated in RHP had little effect on the properties of the plastic, but at the end of the beneficial product life cycle, the plastic could be rapidly degraded.
Within a week of sitting in a bowl of room temperature water, 80% of the polylactic acid fibers deteriorated. Polycaprolactone decomposed in 2 days at a higher industrial compost temperature of 104 degrees Fahrenheit.
How do Enzymes work to compose plastic?
In this study, two different enzymes were used in two different forms of the polyester polymer, but Ramanina Ryan, a professor of chemical engineering and materials science at Michigan State University, who was not involved in the study, said that some of the enzymes were sufficient. This indicates that it stops working at high temperatures. The process may not be practical.
According to Xu, these enzymes work well in hot plastic processing environments. However, researchers will test other plastics made at much higher temperatures to see how well the enzyme can tolerate them.
These enzymes will be incorporated into new plastics in the future. Placing the enzyme over the existing plastic has no effect. If the enzyme was only standing on plastic, it would have a smaller space to work on. Therefore, due to its structure, the plastic cannot be disassembled. Xu explains that “degradable plastics are semi-crystalline,” which makes it difficult for enzymes to penetrate the structure and decompose. Enzymes gain access to these more ordered chains by embedding them in the plastic structure itself.
According to Narayan, it is important to understand that the destruction of plastics will ultimately be affected by the global situation. It is important to consider both the plastic and the world it ends in, rather than dealing with “modifying the polymer outside the receptor biological system”.
This indicates that research on biodegradable plastics not only provides an assessment of the material’s degradation, but also the properties of the ecosystem in which it is supposed to degrade. For example, a plastic intended to degrade in an industrial composting plant does not mean that it is not biodegradable, but it does not degrade as if it were discarded in freshwater. After all, even the best recipes can fail if not baked at the right temperature.
Fortunately, the enzyme that makes this plastic highly degradable is not expensive, according to Xu. One of her former students has already started a business focused more on manufacturing biodegradable plastics, and even industry partners and customers will be joining a more competitive disposable plastic prescription in the near future. You can do this.