Technological watch

What’s new in PHA bioplastics: An update with Cambridge Associates

Nearly all articles found at PlasticsToday center on a fresh news of some sort, whether it’s business, technology or something else.

This time, a story lead was generated by an atypical source: our readership, who collectively continued showing high interest on a monthly basis for one particular feature from April 2018, PHA bioplastics a ‘tunable’ solution for convenience food packaging.

The reason? Continued curiosity in bioplastics in general and a particular fascination with the unique properties of polyhydroxyalkanoates, aka PHA (broad range of uses is shown in the chart above).

“PHA’s most exciting feature is that it possesses a ‘tunable’ property set,” explained Catherine Joce of Cambridge Associates (Cambridge, England) in that feature. “PHA is not one chemical structure, it is actually a whole family of related polymers. Depending on the production process and the feedstocks used, different polymers with different physical properties can be produced.”

If there’s that much current interest in an older article, why not check in with the consultancy and find out what’s new? So we did, and it turns out there’s a lot going on. This update is courtesy of the expertise of Steve Thomas, the firm’s senior consultant, who answers our many questions about this specialty bioplastic.

What feedback did the company receive from that first article that proved so popular with our readers?

Thomas: The article gave rise to a lot of interest. The whole plastic pollution issue has had lots of people looking for more sustainable alternatives to traditional plastics.  Many companies don't have the option to move away from plastic altogether, so they've been investigating bioplastics as an alternative.

How would you characterize the interest in these materials now?

Thomas: The U.S. has been surprisingly switched on about the whole area.  We've had some large companies looking to make their plastic consumables more sustainable.  We've also had some financial institutions who are interested in pushing their portfolio companies in a more sustainable direction.  PHAs and other bioplastics are an interesting potential solution to some of these problems but we're encouraging everyone to look at their whole product lifecycle and the user journeys involved with their consumables. Design for end of life is a very important aspect of sustainability.

What’s been the firm’s activity in PHA these past 12 months since that article appeared?

Thomas: Over the last 12 months we've worked with several companies to analyse their product strategies.  We've also been contacting many bioplastic vendors in order to build a database of different materials that are available.  More recently, our Synthetic Biology Group has begun work on engineering bacterial strains to grow PHAs in our own labs.  We're very excited about this piece of work because it brings the whole story full circle.

What has the company learned about PHA and other biodegradable polymers since then?

Thomas: We've learned that biodegradable plastics are only a small part of any solution.  To be effective, you must design your product to make proper disposal an easy option for the user to take.  It's really important to think of the whole product lifecycle.  For example—PLA (polylactic acid) is a more common biodegradable plastic than PHA.  It's clear and looks a lot like PET so people make drinking cups and bottles out of it.

Unfortunately, you need the really harsh conditions of industrial composting to get it to biodegrade.  So, you don't really benefit in making product out of PLA if you're going to release it in a city that doesn't have an industrial compost collection that's willing to take it.  Most places would see it in compostable waste and think it was PET.  You can't put it into your recycling because it will contaminate the other plastics.  The only option is to send it to landfill—where it won't actually degrade.

By contrast, PHA will degrade in regular compost and will also degrade if it's discarded in the environment. We've worked through some life cycles for some disposable products where we've modified the product design to make it more likely for the user to take it home and put it in their compostable waste.  We've selected PHAs for some of those designs to cover the inevitable cases of improper disposal–when a user disposes of the product by discarding it in the environment.  PHA will degrade in soil and in the ocean as well. but it isn't instant—it will still persist for several weeks or longer if the plastic is thick.

One of the other things that we've learned about biodegradable plastics is that the industry is still very embryonic.  A large proportion of the companies marketing PHA and other biodegradable plastics do not yet have full production capacity. Very few of them will agree to sell you materials and instead want to enter into six-digit development programs. This makes it tough for companies (especially smaller ventures) to look at producing products in bioplastics.  And there are only a very small number of practical suppliers to work with.

Next: Applications, latest research and more

Publication date: 08/07/2019

Plastics Today


This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 837761.