Yeast for Toxic Waste Clean-Up

Wednesday, January 10, 2018 @ 01:01 PM gHale


About 46,000 nuclear weapons ended up built during the Cold War era, leading to tremendous volumes of acidic radioactive liquid waste seeping into the environment.

The end result is these waste sites need to be cleaned up before it harms the environment more than they already have. One answer may lie with yeast.

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Yeast as a potentially safer and more cost effective way to help clean up these radioactive waste sites, according to a new study is entitled “Prospects for Fungal Bioremediation of Acidic Radioactive Waste Sites: Characterization and Genome Sequence of Rhodotorula taiwanensis MD1149.”

One red-pigmented yeast, Rhodotorula taiwanensis MD1149, is extremely resistant to acute and chronic forms of gamma radiation, heavy metals and acid, according to a team of scientists at the Uniformed Services University of the Health Sciences (USU). These characteristics are essential for bioremediation: Clean-up of environmental wastes using micro-organisms.

The team examined 27 yeasts isolated from diverse environments, testing to see how each was suitable for bioremediation under highly radioactive and acidic conditions. The yeast Rhodotorula taiwanesis strain MD1149 was found to be the most resistant to acid and gamma radiation.

After subjecting this microorganism to whole genome sequencing, they discovered it shares resistance traits with Deinococcus radiodurans, a radiation-resistant bacterium which USU researchers have been engineering for bioremediation since 1997.

Papers previously published on potential use of genetically engineered Deinococcus bacteria for clean-up of radioactive wastes, but many of the sites are too acidic and do not support growth of this extremophile.

“In this collaborative study, we showed that yeasts are far better suited when it comes to acid and heavy metals,” according to USU adjunct assistant professor of Pathology Dr. Rok Tkavc, the study’s first author and a Henry M. Jackson Foundation for the Advancement of Military Medicine contract staff scientist at USU.

Moreover, Tkavc said, “MD1149 can attach to surfaces such as rocks and sand, thereby slowing migration of pollutants into the environment. Our findings now offer an alternative strategy to other more expensive and dangerous clean-up approaches.”



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