What is PHA? A Practical Introduction to PolyHydroxyAlkanoates

Plastic is one of the most versatile material groups in modern life. It is lightweight, durable and easy to process, which is why it is used in everything from packaging and consumer products to medical devices and industrial components.

That same durability also creates a major challenge. Conventional plastics can remain in the environment for a very long time and gradually fragment into persistent microplastics.

This is one of the reasons why interest in PHA, or PolyHydroxyAlkanoates, is growing. PHA combines the functionality of a thermoplastic material with a very different production route and end-of-life potential.

At Helian Polymers, PHA is our core expertise. We work with different PHA types, grades and formulations and support customers from material selection through to application development.


PHA is available in different polymer types, grades and forms depending on the intended application.

What is PHA?

PHA stands for PolyHydroxyAlkanoates, a family of polyesters naturally produced by microorganisms. These microorganisms create and store PHA inside their cells as a reserve of carbon and energy.

The polymer can then be recovered, purified and converted into a thermoplastic raw material for further processing.

An important point is that PHA is not one single material. The family contains many different homo-polymers and co-polymers, each with their own combination of stiffness, flexibility, crystallinity, thermal behaviour and processing characteristics.

That variety makes PHA interesting for many different applications.

How is PHA produced?

PHA is commonly produced through fermentation. Selected microorganisms are grown under controlled conditions and supplied with a suitable carbon source. Under the right conditions, they begin to accumulate PHA within their cells.

After fermentation, the polymer is recovered and purified. It can then be supplied as a raw material or further formulated and compounded for a particular processing method or application.

The exact production route differs between manufacturers of specific PHA types, but the basic principle remains the same: microorganisms play a central role in producing the polymer.

Why is PHA different from conventional plastic?

Conventional plastics such as polyethylene, polypropylene and polystyrene are designed to be highly durable. That is useful during their lifetime, but it also means they can persist in the environment for many years.

Over time, these plastics can fragment into increasingly smaller particles, creating persistent microplastics.

PHA follows a different pathway. PHA can be biodegraded by naturally occurring microorganisms under suitable environmental conditions. Instead of simply fragmenting into smaller plastic particles, microorganisms can metabolise or digest the polymer and convert it into naturally occurring substances such as water, carbon dioxide and biomass.

PHA can also be produced from renewable carbon sources, creating a different material origin compared with many fossil-based plastics.

This combination makes PHA especially relevant for applications where both material performance and end-of-life behaviour matter.

The different types of PHA

The PHA family includes many different polymers and copolymers.

PHB, or PolyHydroxyButyrate, is one of the best-known members of the family and is generally relatively rigid and crystalline.

PHBV, or PolyHydroxyButyrate-co-Valerate, contains different monomer units that can influence properties such as flexibility and crystallinity.

PHBH, or PolyHydroxyButyrate-co-Hydroxyhexanoate, offers another balance of mechanical and processing properties.

P34HB, or Poly(3-Hydroxybutyrate-co-4-HydroxyButyrate), is another PHA copolymer with its own material characteristics.

These differences allow developers to select or formulate a material around the requirements of a specific product.

Helian works with several of these raw PHA building blocks, including PHB, PHBV, PHBH and P34HB.

How can PHA be processed?

Depending on the grade and formulation, PHA can be processed using many familiar plastics technologies, including injection moulding, extrusion, blow moulding, film processing, thermoforming, coating and fibre processing.

The suitable material depends strongly on the processing method and the requirements of the finished product. A PHA intended for an injection-moulded component may require different properties from one designed for film extrusion or coating.

This is where Helian's expertise goes beyond simply supplying material. We support customers with material selection, formulation, compounding, testing and processing trials to help develop a PHA system that works in practice.

Where can PHA be used?

PHA can be used in a wide range of applications, and that range is growing quickly. New PHA products and use cases are being developed all the time as companies, researchers and manufacturers learn more about the different properties within the PHA family.

Today, PHA is already used in areas such as packaging, consumer products, agriculture, coatings, fibres, adhesives and biomedical applications. It is also widely used in research and material development, where universities, research institutes and companies continue to explore new formulations, processing methods and applications.

Because PHA can be adapted through different polymer types, blends and compounds, its potential is broad. As the technology develops and more grades become available, new applications continue to appear almost every week.

From raw PHA to a finished application

A PHA project can start at different stages. A university may need a small amount of raw polymer for research, while a company may already have a product concept and need support in finding the right material and processing route.

Helian works across these stages.

We supply raw PHA building blocks for research and formulation, offer PHA-based compounds through PHAradox, and support bespoke material development for more specific applications. This can include compounding, analytical testing, injection moulding trials, sheet or film production and consultancy.

The aim is not simply to supply a polymer, but to help turn it into a material that performs in the intended application.

Choosing the right PHA

The right starting material depends on what the final product needs to do.

Important questions include the processing method, required stiffness or flexibility, thermal behaviour, mechanical performance and intended end-of-life.

Datasheets provide useful guidance, but practical testing is often essential. Processing the material in the actual application gives the information needed to move from a promising polymer to a working product.

That combination of material knowledge and application development is where Helian adds value.

Why PHA?

PHA brings together several interesting characteristics in one material family. It can be produced by microorganisms, can use renewable carbon sources, can be processed with established plastics technologies and offers a broad range of material properties.

At the same time, PHA can biodegrade through microbial activity rather than leaving behind persistent plastic particles.

For companies and researchers looking for new material solutions, that combination makes PHA a highly interesting platform for development.