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US experts have made the first true biodegradable plastic that breaks down into its constituent parts in just a few weeks when exposed to heat and water.

On the other hand, the biodegradable plastic commonly used today does not decay during typical composting. As a result, they just pile up in landfills and add up to the growing amount of regular plastics that take many years before they break down.

The new biodegradable plastic is embedded with polyester-eating enzymes that are protected by a special polymer wrapping, according to MailOnline. It is unlike the composition of the so-called compostable plastics currently available that are made up of a polyester called polylactic acid (PLA).

 First True Biodegradable Plastic Disintegrates in Heat and Water In Just A Few Weeks
(Photo: Wikimedia Commons)
Decaying plastic bag looking like a jellyfish.

Biodegradable Plastic Disintegrates Into Lactic Acid That Feeds Soil Microbes

The study, entitled "Near-complete depolymerization of polyesters with nano-dispersed enzymes" published in the journal Nature, reported that the biodegradable plastic was embedded with PLA and polycaprolactone (PCL) that are commonly used in compostable plastics.

PLA and PCL are enzymes that have the ability to break down the plastic and turn it into lactic acid, which can feed microbes in soil when the conditions are right, IFL Science reported.

The scientists covered the polymers with the enzymes and then embedded them into the plastic fibers. The polymer fabrics were unchanged and because of the enzymes, it disintegrates when exposed to both water and heat.

The special PLA enzyme degraded in just six days at 122 degrees Fahrenheit (50 degrees Celsius), while the PCL degraded at 104 degrees Fahrenheit (40 degrees Celsius) in just two days. Given the right conditions, the biodegradable plastic could break down for up to 98% into small molecules but does not leave microplastics behind.

As plastic pollutants increases, people have become more acceptable and prepared to use biodegradable plastics for single-use plastics, senior author Professor Ting Xu said. The new biodegradable plastic they made solves the continuing problem of biodegradable plastics that decomposes at the same rate as non-biodegradable plastics.

ALSO READ: Biodegradable Plastics Using Carbon Dioxide & Sugar Degrades Back To Original State By Soil Bacteria Enzymes


Biodegradable Plastic Do Not Degrade in Room Temperature

According to Science Daily, even a shirt made with the special enzymes used in the new biodegradable plastic will not degrade when washed because this could withstand sweat and washing at moderate temperatures.

That is what researchers observed when they soaked the special enzymes at room temperature for three months. But when they soak it in lukewarm water it degraded over time.

Xu is developing special enzymes that degrade other types of polyester plastics but also tries to modify them so that they can program the enzymes to stop at a specific point and do not completely degrades.

In that way, plastics could be remelted and turned into new plastics. It could serve as useful for making new materials in the field or repurposed for different use.

"Think of having a damaged equipment or vehicle parts that can be degraded and then re-made in the field, or even repurposed for a totally different use," Dr. Dawanne Poree, ARO program manager said. "It also has potential impacts for expeditionary manufacturing."

RELATED ARTICLE: Machine Learning and AI Can Now Create Plastics That Easily Degrade

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