Extremophile key to nuclear waste disposal

A subterranean bacterium could solve the problem of how to dispose of nuclear waste say researchers at the University of Manchester. This is the first time a microbe capable of surviving in the harsh conditions expected in radioactive waste disposal sites has been found. This extremophile was found in an industrial site in the Peak District which suffers from severe contamination with highly alkaline lime kiln wastes. These conditions mimic those expected in cement-based radioactive waste. When groundwaters reach these underground vaults, they react with cement, becoming highly alkaline. This in turn drives a series of chemical reactions, triggering the breakdown of various cellulose materials in the waste. However, researchers believe this extremophile could negate any potential problems. The bacteria use isosaccharinic acid (ISA) – which binds to unstable and toxic radionuclides – as a food source. Once bound, the radionuclides become soluble and could find their way into drinking water or the food chain. “We are very interested in these Peak District microorganisms. Given that they must have evolved to thrive at the highly alkaline lime-kiln site in only a few decades, it is highly likely that similar bacteria will behave in the same way and adapt to living off ISA in and around buried cement-based nuclear waste quite quickly,” Professor Jonathan Lloyd, from the University's School of Earth, Atmospheric and Environmental Sciences, said. "Nuclear waste will remain buried deep underground for many thousands of years so there is plenty of time for the bacteria to become adapted. Our next step will be to see what impact they have on radioactive materials. We expect them to help keep radioactive materials fixed underground through their unusual dietary habits, and their ability to naturally degrade ISA." The ultimate aim of this work, published in ISME Journal, is to improve understanding of the safe disposal of radioactive waste underground. Microbial degradation of isosaccharinic acid at high pH