Scientists develop biodegradable plastic from cassava starch

[圣保罗]巴西的一支科学家团队开发了可生物降解的塑料foodpackaging or carrier bags, by applying ozone gas to cassava starch.

臭氧（O₃) gas changes the molecular properties of the starch from the root vegetable to produce a bioplastic 30 per cent tougher than those made of the starch of potato, rice or maize, the researchers say.

The world currently produces around 300 million tonnes of plastic waste every year — equivalent to the weight of the entire human population — according toUN Environment.

“我们的测试表明，这种新技术能够产生一种像石油制成的传统塑料一样强的可生物降解塑料，”

Carla Ivonne La Fuente Arias, University of São Paulo’s Luiz de Queiroz College of Agriculture

Carla Ivonne La Fuente Arias, a chemistry engineer at the University of São Paulo’s Luiz de Queiroz College of Agriculture, toldSciDev.Net：“我们的测试表明，这种新技术能够产生一种像石油制成的传统塑料一样强的可生物降解塑料。”

The ozone gas has also enabled them to improve the transparency of the cassava-based plastic, according to Arias, lead author of thestudy publishedin the国际的Journal of Biological Macromolecules.

Arias said she and her team had requested the patent for their invention and were in talks with a number of companies about developing the技术, but production costs remain unclear.

她说：“目前，它无疑将高于生产传统塑料的成本。但是，当大规模生产时，它应该下降。”

Bioplastics are considered less harmful to thebeplay足球体育的微博因为它们可能被生生物的作用分解，所以二氧化碳（CO）₂), biomass or water.

Arias is confident that the new material has potential to help tackle the rampant consumption of plastics andpollutiongenerated by their improper disposal.

圣保罗大学海洋学研究所的生物学家亚历山大·特拉（Alexander Turra）认为，塑料废物的问题更复杂，与社会经济问题有关。

“The pollution caused by plastics is related to the way the global economy is structured and also the societies’ consumption logic, which is, in turn, related to the way garbage is discarded,” he said.

“It is essential to think about this in order to change consumer behaviours, even if it involves biodegradable waste,” he points out, although he recognises “this new technological solution is important, and it may act as a palliative measure for the environment.”

An estimated 8.9 billion tonnes of virgin plastic (non-recycled) and secondary plastic (produced from recycled products) have been manufactured since the middle of the last century, when plastics began to be produced on an industrial scale.

About two-thirds of this total — 6.3 billion tonnes — has been discarded as waste, while 2.6 billion tonnes is still in use, according to astudy publishedin 2017 inScience Advances.

The manufacture of virgin plastic so far in the 21st century is equivalent to the volume produced in the previous 50 years. In 2016, production reached 396 million tonnes, says a report by the世界野生动物基金会（WWF）published in March this year.

WWF’s projections indicate that if the increase in production is not contained, the world will have to deal with about 550 million tonnes of the material by 2030.

Turra补充说：“至关重要的是，要防止各种废物，无论是否可生物降解，都无法到达环境。”beplay足球体育的微博

为此，他说，政府should invest in reducing social inequality, tackling access to basic sanitation and efficient waste collection systems, and improving environmental教育.

The study published in the International Journal of Biological Macromolecules is supported by FAPESP, a donor of SciDev.Net.