Yet another potential use for olive oil processing waste has recently been patented by the University of Granada spin off company MISUR, which has developed a substrate for mushroom growth based on the olive oil waste product known as alperujo — or pomace.
The product, obtained from one of the residues left over after the crushing and extraction of olive oil in mills, is marketed by the company as a fertilizer in bags which also contain mushrooms.
As a substrate for the growth of mushrooms, the product has a number of advantages, apart from being an environmentally friendly way to utilize the many tons of waste from the olive oil production process that are produced every year.
Benefits of the new substrate include higher production as a result of the high nitrogen content of the alperujo, which acts as a nutrient for the mushrooms, as well as the presence of polyphenols that act as natural fungicides that give resistance against fungal infections. Research in Argentina has also supported the technique, showing the addition of olive oil waste products to maize- and garlic-based substrates was beneficial for mushroom growth.
The new product is a follow on from previous organic substrates for mushroom growth produced by MISUR, a company that focuses on the utilization of agricultural wastes such as cereal straw with acidity regulators, nutrients and fungi seeds, which are known as mycelia. The addition of the olive oil byproduct to these types of substrates provides extra material for the fungi to degrade and use as fertilizer for growth.
The Spanish company is currently focusing on the common mushroom and shiitake varieties, the latter of which has a high gastronomic value in Spain despite its Asian origins, and is the first company to produce organic substrates for both species.
Using olive oil waste as a substrate for mushrooms has previously been seen as an effective technique to neutralize the pollutant effect of olive oil waste that is produced in such large amounts throughout the Mediterranean region. However, it has not been successfully marketed for the growth of edible fungus before now.
MISUR products are currently being marketed throughout the region of Andalucia in southern Spain.