OYSTER mushrooms could help vineyard owners clean up their act鈥攁nd make feed for farm animals into the bargain.
Vineyards in Mexico alone produce 270,000 tonnes of waste each year, 93 per cent of which consists of dormant or diseased twigs and leaves that are pruned to keep the vines in shape. These clippings are usually a nightmare to get rid of, but Mart鈥檔 Esqueda and his team at the National Autonomous University of Mexico鈥檚 labs in Hermosillo, Sonora State, say there鈥檚 a solution. They have shown that Pleurotus ostreatus, the world鈥檚 third most popular edible mushroom, thrives on the waste.
Prunings are normally burnt to prevent the spread of disease in the vineyard. But the smoke and carcinogenic chemicals this produces pose a risk both to the environment and to human health, Esqueda says. Now his team has found a way to get rid of the waste by using it to grow mushrooms鈥攁nd using the broken-down waste as animal feed.
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The researchers filled plastic sacks with the waste and incubated mushroom spores in them in darkness. The mushrooms grew well. They tried the same approach with grape pomace, the mixture of seeds and skins left after grapes have been pressed for their juice, but the prunings alone worked best.
Esqueda thinks this is because the prunings are rich in the woody polymers lignin and cellulose. These are the ingredients which enable the mushrooms to grow on decaying logs and the stumps of hardwood trees. Prunings are also rich in sugars favoured by the mushrooms, and low in the fats and nitrogen that appear to make pomace less appetising to the fungi.