In the struggle against pollution, the humble mushroom could prove to be a valuable tool

Research into the humble mushroom — an important dietary staple for many of us — suggests that the waste left over from growing fungi could have a surprising sustainable use.

A study by researchers from Utrecht University in the Netherlands found that the residual waste from the cultivation of white button mushrooms can be used to purify water.

"The nice thing about this waste stream is that it has a low value and so, we can make it more valuable," Brigit van Brenk, one of the researchers behind the study, told CNBC via telephone.

The team of researchers explained in the study, which was published in April, that the white button mushroom is among the types of fungi that produce enzymes which degrade lignin — a polymer that has structural properties in wood and plants. These enzymes have also been shown to break down other substances.

The researchers noticed that there hadn't been much use for the substrate left over from harvesting these mushrooms in the Netherlands, with large quantities sent to Germany to be used as fertilizer instead. Substrate acts as a medium for cultivating mushrooms, playing a similar role to soil when growing plants.

With that in mind, the researchers decided to test out how effective the leftover mushroom substrate could be in removing contaminating substances from water. They added eight substances to water, including herbicide chemicals, caffeine and pharmaceutical drugs, and then combined this with fragments of the substrate.

They found that depending on the substance, as much as 90% of these organic micropollutants had been removed from the water across a seven-day period.

In the U.K., in particular, concerns around water pollution have been growing. In findings published last year as part of an