Altered Algae Eat More Metal To Clean Up Lake Erie

Bio-remediation researchers supported by Ohio Sea Grant funding are further enhancing genetically altered algae to maximize its ability to pick up trace metals. 

Metals such as mercury, cadmium and zinc from area industry accumulate in Lake Erie sediment and eventually pose a human health risk. 

The algae, Chlamydomonas reinhardtii, is a unicellular algae that is widely available, can be genetically engineered easily, and grows quickly in high volumes.

Previous research by Ohio State University researcher Richard Sayre found the algae to be more effective, less costly and safer than using chemical extraction methods. 

Now, Sayre and his team have found further ways of altering the algae to increase the algae's ability to attach itself to heavy metals in Lake Erie sediment. They used three approaches of genetic alteration, and found that each enhanced the cell's ability to bind with the metals.

The most effective method involved attaching metallothionen, a protein that binds heavy metals, to the outside of the algae cell. It picked up five times more metal than a regular cell and grew three times faster when surrounded by high concentrations of heavy metals. 

Research will continue to study how much of each trace metal binds to the Chlamydomonas cell. Sayre will also work with engineering firms to test pilot facilities for treatment of contaminated wastes and sites. They envisage using dead, freeze-dried algae in filters to treat contaminated sediments and discharges that flow into Lake Erie. Significantly, live algae would not be released into the environment.

"By increasing the algae's ability to attach to trace metals, we believe this research will be an important step in the identification of the best strategies for reducing heavy metal pollution and the remediation of contaminated sites and waters of the Great Lakes," Sayre said.


[Contact: Richard Sayre]