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BIOREMEDIATION SPOTLIGHT: ENGINEERED YEAST USED TO SEQUESTER HEAVY METALS

Posted on January 22nd, 2020

Microscopic view of Saccharomyces cerevisiae

Microscopic view of Saccharomyces cerevisiae

Craig Venter, American biochemist and leading scientist in the first draft sequence of the human genome, made the prediction that “If the 20th century was the century of physics, the 21st century will be the century of biology.”  This statement holds true in the field of remediation, a field that embodies JM Sorge’s mission of practical solutions to complex and continually changing environmental problems.  This will be the first of a series of posts specifically placing a spotlight on bioremediation.

According to the USEPA, bioremediation is an engineered technology that modifies environmental conditions (physical, chemical, biochemical, or microbiological) to encourage microorganisms to destroy or detoxify organic and inorganic contaminants in the environment. Environmental scientists and engineers currently utilize a wide range of organisms from plants, bacteria, to even fungi for these purposes.

As presented in the November 25, 2019 edition of Chemical & Engineering News, researchers at the Massachusetts Institute of Technology (M.I.T.) have turned to yeast for an inexpensive, easy to engineer, adaptable organism for the sequestering of heavy metals in contaminated soils. Plants that can absorb and tolerate high concentrations of heavy metals are also useful in this regard but can be costly due to longer lifecycles and specific ecological growing requirements. Saccharomyces cerevisiae, a species of yeast that has been instrumental in brewing, baking, and winemaking for millennia, allows researchers to easily engineer their metal transporter proteins, which are analogous to metal transporter proteins in plants.

These engineered yeasts now have hyperaccumulation tendencies that have been further designed to be selective for specific metals such as chromium, arsenic, cadmium, and even the radioactive strontium-90 isotope. These metals have been demonstrated to be a costly contaminant to remediate at industrial sites throughout the United States.  When Dr. Angela Baker (M.I.T.), a lead researcher, was asked about recovery of accumulated metals in the yeast she noted, “Yeast cells collected after internalizing heavy metals can by lysed and fractionated from the collected metals. The metals can be further purified using traditional chemical processes, and the digested cells can be used as yeast extract to feed the next batch of yeast. We have not yet measured efficiency of recovery.”

Bioremediation utilizing these yeasts could prove to be an invaluable resource moving into a future where more environmentally sensitive remediation is required. JM Sorge will be following research on this and other green technological advances as we move further into the 21st century.

Links:

For more information visit C&EN’s website:

https://cen.acs.org/topics/biological-chemistry.html#syntheticBiology

For more from Dr. Belcher and her team visit:

http://belcherlab.mit.edu/

 

Joseph Todd

Environmental Scientist


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