Renewable bioplastics go under the microscope

A team from the University of Warwick, in conjunction with company Biome Bioplastics, is studying how 100 percent renewable bioplastics could be created.

The research team is hoping to do this by deriving chemicals from the breakdown of a waste product from paper manufacture, called lignin.

This should not only create cheaper, stronger and more environmentally-friendly bioplastics, but improve their performance.

The majority of bioplastics are made with chemicals which are usually found in oil or renewable biomass. These tend to be more expensive and also less useful than traditional polymers.

Professor Tim Bugg led a group of scientists at the University’s Centre for Biotechnology and Biorefining to discover a new enzyme.

It is produced by bacteria which can break down lignin more cost-effectively than traditional methods.

Warwick has been given a £150,000 grant from the Technology Strategy Board to work on this project with Biome Bioplastics.

The aim is to discover whether it is possible to bring this process up to a commercial scale.

“The key element of it is [asking] can we use bugs to do things that chemical plants do?” the CEO of Biome Bioplastics, Paul Mines, told the Engineer.

“And in doing so can we do it in a less capital-intensive way than a chemical plant with a very low cost for material?”

Lignin is one of the most abundant organic compounds on Earth, and is a main components of plant structures.

It is formed from rings of carbon atoms which can be bonded with other molecular groups, making it particularly useful. It is known as an ‘aromatic’ chemical.

“Aromatic chemicals tend to provide higher functionality than long, straight chains in polymer,” Mr Mines added, “But lignin is a horrendous molecule to get things out of.”

By examining the different pathways by which the enzyme breaks down the lignin, the research team may be able to bring down the cost of bioplastics two to four times, making it very similar to the cost of petrochemical plastics.

The aromatic chemicals could improve the flexibility, strength and performance at high  temperatures, which means they could also have additional uses.
“At the moment we’ve got bioplastics that function at up to 100ºC,” said Mr Mines, “That prevents things like automotive work because when you make a car you want to make sure the plastics are good for high temperatures as well.”