As the harmful effects of plastic pollution become increasingly apparent in today’s world, the search for innovative materials has become a top priority. New innovative materials should meet various conditions to compete with traditional plastics. The polymer needs to be able to cope with different thermal conditions so that complex shapes can be created from them. So far, known polymers have a very small processing window and degrade with temperature deviations. In our quest for more sustainable materials, we must also look for natural polymers that are degradable, non-toxic, and do not leave microplastics behind. Last but not least, we are looking for a material that is mechanically flexible but durable and chemically resistant at the same time.

So far, this has not been achieved with previous polymers. And so this miraculous bio-based polymer with the tongue-twisting name of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), familiarly known as PHBH, appears on the scene. At Refork, this polymer has become an indispensable ingredient in our products. So, let’s take a closer look at PHBH and delve deeper into its vital role in reshaping the future of plastics.

Concepts of ecology and earth pollution. Pile of different plastic waste.

What makes PHBH unique? 

PHBH is made entirely from renewable resources and represents a significant shift from petroleum-based plastics. What really sets PHBH apart is its exceptional capacity to biodegrade. Unlike traditional plastics, which persist in the environment for centuries, PHBH undergoes faster degradation, significantly reducing its environmental impact. PHBH is produced by naturally occurring microorganisms and does not deplete our already compromised non-renewable resources. 

How is PHBH produced? 

Kaneka Corporation’s breakthrough microbial fermentation process is the basis for PHBH production. This process utilizes the power of microorganisms to convert biological oils into PHBH. What is truly remarkable is the precision with which researchers can control the composition of the 3-hydroxyhexanoate units, allowing them to tailor the properties of PHBH to suit specific applications.

PHBH detail shot.

Revealing the impressive properties of PHBH

1. Thermal stability: Compared to its counterparts like PHB or PHBV, PHBH has a broader processing window and excellent thermal stability. This property is essential for various manufacturing processes and ensures consistency and reliability of production.

2. Strength: The unique blend of highly crystalline 3-hydroxybutyrate (3HB) and 3HHx elastomeric units gives PHBH impressive mechanical strength. It resists stress and deformation, making it suitable for a wide range of applications that require durable but flexible materials.

3. Biodegradability: PHBH’s ability to biodegrade sets it apart from traditional plastics. Soil microbes and aquatic organisms play a crucial role in the breakdown of PHBH, ultimately leading to its degradation into natural by-products, thus minimizing environmental damage. As one of the few, PHBH has OK compost HOME certification and, therefore, can decompose even in regular home compost without the need for highly energy-intensive industrial disposal. 

PHBH in action

Medical Devices: Currently, PHBH is still a relatively expensive polymer, but its low cytotoxicity makes it suitable for medical use. Surgical suture materials, drug delivery systems, and tissue engineering are just a few examples of PHBH properties that meet the stringent requirements of the medical industry.

Packaging materials: Forward-thinking companies are using PHBH for packaging solutions. Its ability to degrade naturally aligns with circular economy principles and offers a sustainable alternative to traditional plastic packaging, which often ends as waste. At Refork, this polymer has become part of our products and helps us further enhance the sustainability of our cutlery and straws.


PHBH represents a significant milestone on the road to a more environmentally sustainable future. Its sustainable production, impressive properties, and versatile use make it a valuable ally in the fight against plastic pollution. As we continue to face the challenges presented by plastic waste, PHBH is a shining example of innovation and sustainability. By embracing PHBH, we take a step closer to creating a world where materials are not only functional but also environmentally responsible, leaving a positive legacy for generations to come.

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