A Bioplastic Bottle Made From Olive Skins
A researcher working with a mill in the Sierra de Segura has pulled a biodegradable plastic out of the one part of the olive nobody has found a use for: the skin left in the pomace. Jesús Zorrilla, a pharmacist based in Málaga with family roots in Orcera, extracted polyhydroxyalkanoates from the alperujo of picual olives and used them to make food-grade containers. Here is what was done, what it could be worth to a mill, and what still has to be proved.
What was made
Polyhydroxyalkanoates, known as PHAs, are polyesters produced by bacteria. They are not new, and they are already used for biodegradable packaging elsewhere. What is new here is the feedstock: the olive skins in alperujo, the wet paste left over after two-phase extraction, which mills currently pay to dispose of or send to a pomace extractor.
The work was done with Potosí 10, an oil company at Orcera registered with the Sierra de Segura denomination of origin, which supplied both the picual alperujo and the use of its plant. The resulting plastic, according to the researcher and the denomination, is non-toxic and fully biodegradable.
Why a bottle made from olives would suit olive oil
Two arguments are being made for it. The first is that a bioplastic container avoids the risk of compounds migrating out of conventional petroleum-based plastic into the oil, a concern raised about storing oil in ordinary plastic for long periods. The second is that the material offers protection against the oxidation caused by light.
Both claims need independent testing before anyone should repeat them as fact, and the project is still at the patent stage. Even so, the direction is right: olive oil is a fat that sits on a shelf for months, and packaging is one of the few places where a producer can still protect quality after the oil leaves the mill.
The number that will decide this
The figure being circulated is the interesting part. A mill processing about 10,000 tons of olives a year could obtain some 30,000 kilos of bioplastic, worth roughly 200,000 euros of extra revenue. For a cooperative mill in Jaén, with olive oil selling below the cost of production, that is not a rounding error.
| Item | Claim |
|---|---|
| Feedstock | Olive skins in alperujo from two-phase milling |
| Output per 10,000 tons of olives | About 30,000 kilos of bioplastic |
| Extra revenue | About 200,000 euros a year |
| Stage | Patent in development, seeking industrial partners |
- Nothing in this replaces the oil business. It changes what a mill does with its waste.
- Alperujo is already burned for energy and extracted for pomace oil, so the bioplastic has to outbid those uses.
- Scaling a laboratory yield to a working mill is where most byproduct projects stop.
Olive waste has been a research subject for years, from turning olive stones into bioethanol to using mill waste to strip heavy metals out of sewage. The reason the subject matters is simple enough: untreated, the same material pollutes rivers and ponds.
Packaging is the part of quality a producer controls last and abandons first. Clear plastic and clear glass let light in and oil goes stale in months; dark glass, tins and bag-in-box do not. Whatever happens to this bioplastic, the practical lesson holds today: if you can see the oil through the bottle on a lit shelf, so can the light that is wrecking it.