Good News Notes:

“Trees, crops and even organic waste can be transformed into a bewildering array of plastics to use in products ranging from single-use bags to heavy-duty airplane wings.

These so-called biopolymers could play a vital role in weaning us off petroleum plastics—which will help cut greenhouse gas emissions, and ensure plastics come from a renewable resource.

And in some cases they could help to reduce plastic pollution. One of the major sources of plastic pollution is packaging, which accounted for nearly 40% of the plastic used in the EU in 2019, according to Plastics Europe, a trade association.

Researchers have developed ways to make biodegradable food waste bags and food packaging from municipal food and garden waste.

“You are transforming organic waste to make a waste bag, which is biodegradable. So you are closing the cycle—you don’t use other materials to make the (plastic) bag,” said Thomas Dietrich, an engineer in biotechnology at Spain’s TECNALIA, a research and technological development center.

Dietrich is project manager of a project called VOLATILE, which has developed a technology that can be integrated into existing municipal anaerobic digestion and composting plants. It uses microorganisms to break down organic waste into volatile fatty acids, which are the building blocks of the PHB and PHBV plastics used to make plastic bags and food packaging.

The main by-product is a residue which can be used to make compost. Hydrogen gas is another by-product, and it can be used to make electricity.

Biodegradable

Using biowaste to produce biodegradable plastics could help solve a major challenge caused by the majority of biodegradable plastics currently being used.

“Normally the big (industries) selling (biodegradable plastics) on the market use food-grade agricultural materials,” said Dietrich.

Because of the volumes needed, it will not be possible to use agricultural produce to replace petroleum-based packaging without competing with food crops or biofuels for agricultural land, said Dietrich.

“So we have to try to keep organic carbon in the economy without falling back on agriculture,” he said.

Plastic bags and packaging made with VOLATILE’s technology would end up in household biowaste and in theory could be used once more to produce volatile fatty acids—although this has not yet been tested by the VOLATILE team.

One of the main challenges to this type of system is the lack of composting plants in most regions of the world, including Europe.

Across the EU, up to 50% of municipal solid waste is organic, and only about 40% of biowaste is recycled into high-quality compost and digestate, says the European Compost Network. The majority goes to landfill or for incineration.

However, this is likely to improve. The European Environment Agency says recycling more municipal bio-waste is ‘crucial’ for meeting EU targets to recycle and reuse at least 60% of all waste by weight by 2030.

Composition

Whether plastics are biodegradable or not is due to their chemical composition—not their origins. So petroleum-based plastics can be biodegradable, and plant-based ones can be non-biodegradable.

However, a shift to biopolymers would help reduce greenhouse gas emissions produced to make the plastics—even if the end product is not biodegradable.

“We need to achieve this (shift) in 10, or maximum 15, years because the climate stakes are so high,” said Vincent Placet, a research engineer at the FEMTO-ST Institute in France.

“The quantity of CO₂ emitted to produce wood and plants is very low,” said Placet, adding that they also absorb atmospheric CO₂ during growth. He coordinates a project called SSUCHY, which is developing load-bearing bio-based composites for use in automotive and aerospace industries.

Biopolymers derived from trees and crops are already used to make car interiors.

Other biopolymers are being developed to be load-bearing. These include thermoset plastics which are designed to last up to 30 years under harsh conditions—in airplane wings and bodies for example….”

View the whole story here: https://phys.org/news/2021-05-tree-bark-compost-aircraft-wings.amp