Polyhydroxyalkanoates (PHA): The promising bioplastic with challenges to scale

In the quest for sustainable alternatives to conventional plastics, polyhydroxyalkanoates (PHAs) have emerged as a promising solution. These naturally occurring polyesters, produced by microorganisms under specific conditions, offer a unique combination of biodegradability and versatility that positions them well in the evolving materials landscape.

What Makes PHAs Special?

PHAs come in various forms, primarily categorized as short-chain length (scl-PHAs) and medium-chain length (mcl-PHAs). The most common type, polyhydroxybutyrate (PHB), was discovered in 1925 and has since been joined by numerous variants with tailored properties.

What sets PHAs apart from other bioplastics is their complete biodegradability in multiple environments. Unlike PLA, which typically requires industrial composting facilities, PHAs can break down in home composting systems, soil, freshwater, and even marine environments. This makes them particularly valuable for addressing plastic pollution in oceans, where conventional plastics persist for decades or longer.

PHAs also boast impressive material properties, including good barrier characteristics for oxygen and moisture, UV resistance, and printability. Depending on the specific formulation, they can range from rigid thermoplastics similar to polypropylene to flexible elastomers resembling rubber.

Production Methods and Challenges

The primary commercial route for PHA production is microbial fermentation, where bacteria convert carbon sources into polymer granules within their cells. Three main feedstock approaches exist:

1. Sugar fermentation - Using glucose, sucrose, or other sugars as carbon sources

2. Vegetable oil fermentation - Using plant oils like palm or soybean oil

3. Methane fermentation - Using methane from natural gas or biogas

Each method has its advantages and challenges. Sugar fermentation currently offers the lowest production costs, while methane fermentation could potentially utilize waste gas streams, creating a circular economy opportunity.

However, all production routes face significant economic hurdles. Current PHA production costs have a wide range depending on the process and region, and are significantly higher than  conventional polyolefins per ton. This substantial cost premium remains the primary barrier to widespread adoption.

The high costs stem from several factors:

• Expensive feedstocks (40-60% of production costs)

• Energy-intensive fermentation processes

• Complex extraction and purification steps

• Limited economies of scale

Market Applications and Growth

Despite cost challenges, PHAs have found commercial applications in several sectors:

• Packaging: Food containers, films, straws, and coffee cups

• Agriculture: Biodegradable mulch films and slow-release fertilizer coatings

• Consumer products: Cosmetic microbeads and personal care items

• Medical: Surgical sutures, implants, and drug delivery systems

Global PHA capacity reached approximately 115,000 tons in 2025, with the United States and Japan accounting for the majority of production. Leading producers include Danimer Scientific, RWDC Industries, and Kaneka Corporation.

Environmental Benefits

PHAs offer significant environmental advantages over conventional plastics. Their biodegradability addresses end-of-life concerns, while their production from renewable resources can reduce carbon footprints. When produced from waste streams like used cooking oil, PHAs can achieve carbon emissions less than half those of fossil-based plastics.

However, the environmental profile varies significantly depending on feedstock choice. Palm oil-based PHAs, for instance, carry higher emissions due to land use impacts, while waste-based or methane-based routes may offer superior sustainability credentials.

Future Outlook

For PHAs to achieve mainstream adoption, several challenges must be addressed:

1. Cost reduction: Through improved production efficiency, cheaper feedstocks, and economies of scale

2. Policy support: Clear regulatory frameworks that recognize biodegradability benefits

3. Infrastructure development: Expanded composting facilities and consumer education

4. Technical innovation: Enhanced material properties and processing capabilities

The most promising near-term scenario combines sugar fermentation with increased scale and improved technology, potentially bringing costs closer to conventional plastics. With growing regulatory pressure on single-use plastics and rising consumer demand for sustainable materials, PHAs are positioned to play an increasingly important role in the transition to a circular bioeconomy.

While PHAs may not replace all conventional plastics, they offer a valuable solution for applications where biodegradability provides clear benefits, particularly in marine environments and other settings where proper waste management is challenging.

Find out more…

Biorenewable Insights: Polyhydroxyalkanoates (PHA) (2025 Program)

Polyhydroxyalkanoates (PHA), a class of naturally-occurring polyesters, are promising candidates for replacing petrochemical plastics in select applications due to their biodegradability and other desirables properties. This report outlines the production processes for PHA, evaluates the companies that own these technologies (project scoring), and provides cost estimates for plant construction and production. Additionally, the report explores carbon credits and implications for PHA adoption in various sectors including food packaging, consumer products, and medical supplies.

About Us - FGE NexantECA is the leading advisor to the energy, refining, and chemical industries. Our clientele ranges from major oil and chemical companies, governments, investors, and financial institutions to regulators, development agencies, and law firms.  Using a combination of business and technical expertise, with deep and broad understanding of markets, technologies, and economics, FGE NexantECA provides solutions that our clients have relied upon for over 50 years.