For decades, the packaging industry has used “biodegradable” as a badge of honor and that too without always clarifying the fine print. Polylactic acid (PLA), for years was “the darling” of eco-branding, turns out to need industrial composting conditions just to break down back to the earth. If you just stick it in your backyard pile or drop it near a beach, you could be waiting years or decades for it to just degrade and disappear.
Polyhydroxyalkanoates (PHA), on the other hand, operate by an entirely different set of rules. And the science behind those rules is reshaping what “sustainable packaging” actually means.
The Composting Fine Print Most Brands Ignore
The industrial composting process is a highly controlled one, involving high temperatures, normally in the range of 55 to 60°C, and controlled amounts of oxygen and moisture. When operated in such a way, PLA decomposes by more than 90 percent within 90 days. However, this applies in a factory setting only.
The existence of an infrastructure gap is evident. Only 4% of municipalities in the United States have composting programs for food waste, and it is even lower in emerging markets. Packaging labeled as “industrial compostable” can typically be found in landfills where they perform the same way as regular plastic (a lifetime of hundreds of years).
PHA provides an alternative to this issue at the level of its biological basis. PHA is created within a microbial organism and serves as its energy reserve, so microorganisms that are in soil, freshwater or ocean floor sediment will be able to recognize PHA as food. PHA’s polymer will break apart from enzymatic hydrolysis and there are no special temperatures required and there is no need for industrial facilities.
What The Data Actually Shows
Scientific review by PMC in 2024 has examined the biodegradation of PHA across fresh water, seawater, soil, composted products (i.e., backyard & industrial) & anaerobic conditions & has conducted the most complete analysis of biodegradation of any polymer to date. So, all together PHA is fundamentally disposed of in all environments with ecosystems containing microbes/biomass whereas all other major categories of biomass polymers (PLA, PBAT, etc) have major gaps in their biodegradation in one or both of the marine and backyard composting environments.
An article featured in the Scientific Reports Journal (2025) showed that rigid and films made of PHA always degraded during industrial composting. While at the same time, these materials displayed evidence of early decomposition in cases where they were subjected to temperatures outside the norm. Three different families of polymers were tested in the study, and PHA was singled out for its adaptability in nature.
Why “Natural Decomposition” Is Where PHA Wins
PHA’s competitive edge is not just its compostable certification, as there are many such materials. The competitive edge of PHA is in the fact that it doesn’t require certification infrastructure to decompose. In particular, PHA will start decomposing in marine sediments in about a month as marine microorganisms are capable of digesting PHA due to their enzyme systems.
It was shown in a 2023 review published by MDPI regarding bioplastic decomposition in soil conditions that PHA films increased microbial life in soil as they degraded in soil burial experiments. That is, PHA doesn’t just disappear; it feeds the ecosystem it enters.
And compare that to conventional PE and PP packaging, which, under any real-world condition, simply fragments into microplastics. There is no enzymatic pathway for most petrochemical polymers. They don’t biodegrade, they just get smaller, and more dangerous.
Where Terrapha Fits In
TerraPHA isn’t just sourcing PHA but it’s rethinking how the material is produced from the ground up. The company’s proprietary fermentation process achieves 4-5 times higher cell densities than conventional methods, which translates directly to lower production costs per kilogram.
- Waste-first feedstocks. TerraPHA processes crude glycerol from biodiesel, used cooking oil, animal fats, and agricultural sugars inputs that don’t compete with food supply chains and are already being discarded.
- Dual-recovery method. Using both mechanical/enzymatic and biological extraction, TerraPHA maximizes PHA yield while reducing processing waste.
- Scale without compromise. Higher cell density fermentation means brands can access PHA at price points previously out of reach, especially for SMEs and emerging-market manufacturers.
For companies evaluating the industrial composting vs. natural decomposition question, TerraPHA’s materials answer both, certified for industrial composting where that infrastructure exists, and proven to degrade in soil and marine environments where it doesn’t.
So, the next time you see “biodegradable” on a package, ask where. Because for PHA, the answer is: almost anywhere life exists.
Frequently asked questions
Q: Is PHA packaging actually compostable at home, or only in industrial facilities?
In contrast to PLA, which needs high temperatures (55-60°C) from the process of industrial composting to decompose, PHA will decompose in home compost, in soils, and in the sea as well. The decomposition process takes place more slowly when the temperature is not high. However, it happens since ordinary soil or water organisms produce the necessary enzymes for breaking down PHA. There is also TUV Austria “OK compost HOME” label especially designed for PHA products.
Q: How does PHA compare to PLA, the most common bioplastic?
PLA is a material derived from nature, it is not biodegradable unless composted industrially. Under natural conditions on the surface of the earth or sea and at normal temperatures, a thin layer of PLA will take about 11 months to a year before even starting to disintegrate, and the breakdown process will not be complete. On the other hand, PHA is a bioplastic that is decomposed by many more types of microbes compared to PLA and in different environments. PHA does not cause any microplastics.
Q: Does PHA packaging perform as well as conventional plastic in terms of barrier and durability?
Yes, in most cases. PHA is modifiable in terms of flexibility or rigidity, transparency or opacity, offering similar moisture and oxygen barrier characteristics to existing PE and PP plastics. Co-blending PHAs, for example, combining aPHA (amorphous PHA) with PLA, will increase impact resistance. The only disadvantage with PHA has been the high cost of production, which companies such as TerraPHA are currently solving by developing highly efficient fermentative processes.
