What on earth is PHA?
PHA — polyhydroxyalkanoate — is a biopolymer that microbes make from plants — and that other microbes eat when you're done with it. It's the rare lining material that's certified compostable at home, not just in an industrial facility. That's why we line every cupcasa cup with it.
From plant to cup to soil
PHA completes a genuine circle — every stage powered by biology, not petrochemistry.
Grown from plants
PHA starts with plant-based oils and sugars — renewable feedstock, not petroleum.
Brewed by microbes
Bacteria ferment those plant oils and store PHA as natural energy granules — the same way we store fat.
Shaped into cups
The biopolymer becomes the lining of a sturdy paper cup — where PE or PLA would normally go.
Returns to nature
When composted, microbes recognise PHA as food and digest it. No microplastics left behind.
PHA vs. everything else
Not all "eco" cups are equal. Here's the honest comparison.
| Property | PHA (us) | PLA | Paper | Plastic |
|---|---|---|---|---|
| Made from renewable plants | If lined | |||
| Home compostable | ||||
| Industrial compostable | If lined | |||
| No PE or PLA lining | ||||
| Leaves no microplastics | Sometimes |
How to dispose of a cupcasa cup
Home compost bin
Toss it in your backyard compost — it breaks down with food scraps.
Industrial / commercial
Fits standard commercial composting collection where available.
No microplastics
The PHA lining is digested by microbes — nothing fragments into plastic that lingers for centuries.
Composting infrastructure varies by region — check your local guidelines. What sets PHA apart is that it is certified for home composting as well as industrial, which is the part most linings cannot claim.