PLA vs PHA: which bioplastic for food packaging?

By the Compost Ready editors · Updated 12 October 2026

PLA is the cheap, widely available bioplastic built for industrial composting. PHA is the more expensive one made by bacteria, studied for breakdown in a wider range of environments. Both are bio-based polyesters, and both are still plastics in EU law.

Quick verdict

If you need a clear, stiff, low-cost pack for cold food, and your customers have access to industrial composting, PLA is the established choice. If end-of-life outside a composting plant matters to you, or you need something closer to polypropylene in behaviour, PHA is the material to watch, but expect to pay more and to work harder on processing.

Neither one is a drop-in replacement for every conventional plastic. Both usually need help from other layers or additives to protect oxygen-sensitive food.

PLA and PHA side by side

PLA in brief

PLA is made in two steps. First, sugars from a starch-rich crop are fermented into lactic acid, the same molecule that sours milk. Then the lactic acid is chemically linked into long polymer chains. The result is a stiff, glossy plastic that can be made glass-clear, which is why it shows up in deli boxes and cold-drink cups where people want to see the food.

Its weak point is heat. PLA starts to soften once it gets warmer than roughly 55-60 °C, so a PLA cup is fine for iced coffee but not for hot tea, and a PLA box left in a hot car can warp. Higher-heat grades exist, but they need extra processing.

At end of life, certified PLA breaks down well in industrial composting, where the heat helps start the process. In a garden heap, it can take a very long time. And because it looks like PET, PLA that ends up in the plastic recycling bin is unwelcome there too.

PHA in brief

PHA is not synthesised by chemists at all. Bacteria make it as an energy store, packing it into granules inside their cells. Producers feed the bacteria, trigger the storage phase, and extract the polymer. The two forms used most in packaging research are PHB, which is stiff but brittle, and the copolymer PHBV, which is tougher. Our PHA guide explains the process in more detail.

Because microbes in many environments produce enzymes that digest PHA, it is studied for biodegradation in soil and water as well as in compost. That's a genuine advantage over PLA, though it is not a licence to litter, and any claim should still name the standard it was tested against.

The obstacles are practical. PHA costs more to produce, and PHB in particular has a narrow processing window: heat can effect its molecular weight quickly once it melts, which makes moulding and film-blowing fussier than with conventional plastics.

Protecting the food

For food packaging, the polymer on its own rarely decides the outcome. Fresh meat, cheese and many ready meals need a strong oxygen barrier, and neither PLA nor PHA supplies one alone. Researchers solve this the same way conventional packaging does, with multilayer structures. In the EU-funded YPACK project, for example, PHA layers were combined with cellulose nanocrystals to raise the oxygen barrier, and with active layers containing natural antimicrobials.

The catch is that every extra layer has to be compatible with the end-of-life story. A compostable PHA tray glued to a conventional barrier film is no longer a compostable pack.

Which one to choose

Pick PLA when you need transparency, the food is cold or ambient, cost is tight, and the pack is likely to reach industrial composting. Food-service items at events or in closed systems such as canteens are a typical fit.

Look at PHA when breakdown outside an industrial plant is part of the reason for going bio-based, when you need better heat resistance, or when you want the material made from a waste stream rather than a food crop. Expect a smaller choice of suppliers.

Choose neither if a recyclable mono-material pack would do the job and your market has the collection system for it. Under EU policy, compostable plastics are meant for uses where reducing, reusing or recycling isn't possible.