NOW there is another reason to enjoy that glass of cool beer on a hot summer evening. Beer bran, a by-product of brewing beer from barley, can be used to clean polluted waters.
Researchers at Kobe Pharmaceutical University in Japan have demonstrated that the bran adsorbs hazardous organic compounds including benzene and trichloroethane (TCE) from chemical and industrial waste water. The US National Academy of Sciences reported last week that there is growing evidence that TCE, used in adhesives and paint, can cause cancer. The Environmental Protection Agency is carrying out a new risk assessment of the chemical.
Companies commonly use filters made from activated carbon to remove pollutants from water. The dry, porous material has a large surface area, allowing it to trap large quantities of impurities. However, it is expensive and energy-consuming to produce, as it is made by heating coal to around900 °C, says Atsuko Adachi, the project's lead researcher.
Since beer bran is readily available as a by-product of brewing, it is up to100 times cheaper, she says. The way in which the material adsorbs compounds is still unclear, but the researchers believe it is based on intracellular particles called spherosomes, widely found in plants.
In tests, Atsuko found beer bran adsorbed organic compounds at an efficiency of 76.2 per cent for benzene, and 92.5 per cent for trichloroethane. The effect was observed over a wide range of pH levels, meaning it could be used to treat many sources of industrial waste water.