Chalk olive stones up to the list of waste products that can be used as fuel. Researchers from the Universities of Jaén and Granada in Spain have discovered that olive stones—byproducts of processing olive oil and table olives—can be turned into bioethanol.
The new process works by pre-treating the stones with high-pressure hot water and adding enzymes to break down plant matter and create sugars. Hydrolysate obtained from the process is then fermented with yeasts to produce ethanol. The top yield from the process is 5.7kg of ethanol per 100kg of olive stones.
While the amount of olive stones produced as a waste byproduct pales in comparison to other agricultural wastes, we can’t afford to overlook anything in the race for sustainable fuel. After all, the more waste byproducts we use, the fewer food crops we waste on fuel.
Photo Credit: mccullagh.org