Plastic from weed

Sunday 30 September 2012

Water hyacinth can be used to make biodegradable polymer

Water hyacinth is a rich source of carbohydrate polymersWATER hyacinth is considered one of the most notorious aquatic weeds. It proliferates rapidly in lakes, dams and irrigation channels and chokes them. But scientists have now shown that the infamous weed is a rich source of carbohydrate and can be used to make biodegradable plastic.

Past studies have shown that carbohydrates derived from weeds and grass can yield plastic material. This led researchers at Manonmaniam Sundaranar University in Tirunelveli, Tamil Nadu, to turn their attention towards water hyacinth. They found that water hyacinth-derived sugar molecules like lignin, cellulose and hemicellulose can be converted into polyhydroxybutyrate (PHB), a polymer that is a raw material for making biodegradable plastic.

Currently, plastics and synthetic polymers are derived from petroleum-based raw material like polyvinyl chloride and polypropylene. These do not decompose. Plastics developed using PHB are compostable. Also, making PHB from natural resources can reduce cost and harmful gas emissions.

To make PHB, researchers dried and crushed water hyacinth into a fine powder and subjected it to acid and enzyme treatment in the presence of water. The end product was used to grow Cupriavidus necator, a bacterium known to produce PHB, in the presence of organic and inorganic nitrogen sources. As the bacteria grew, PHB was found to accumulate inside them. Researchers ruptured the bacterial cells using an alkaline solution and extracted the PHB. Maximum PHB, 4.3 grams per litre, was obtained from the bacteria cultured using the products of enzymatic breakdown of water hyacinth powder. “PHB can have potential applications in a wide variety of fields such as industrial, biomedical, agricultural, domestic, and automobile,” says lead researcher A G Murugesan.

“The quality of PHB derived from hyacinth is similar to PHB from other sources. The advantage with using water hyacinth as raw material is that it is available free of cost throughout the year,” he adds. The study is set to appear in the October issue of Bioresource Technology.

Move from news to views and get in-depth reports on issues that matter to you, every fortnight.
Subscribe now »

We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.

  • Though I am not a scientist,would like to enquire if Amy other reaching regarding converting plants I to plastics have developed since 2012?
    Stay in South Africa around the Hartbeespoort dam in the North West Province and the dam has very big problem.Poverty is very big problem and work creation would be ideal.via a converting plant.

    Please asvise

    Posted by: René Duffey | one year ago | Reply
Scroll To Top