Nüsslein’s work named a ‘best invention’ by Time
Time magazine has named the work of Klaus Nüsslein, associate professor of Microbiology, and his collaborators as one of the best inventions of 2007. Nüsslein studies a microorganism, dubbed the “mighty microbe” in the Nov. 12 issue of Time, that when injected into loose sand can create cement-like, stable ground. His results were published in the Journal of Geotechnical and Geoenvironmental Engineering.
The soil-dwelling bacteria feed on a nitrogen-based salt, breaking it down to produce ammonia as a byproduct. The more ammonia is released in the soil, the less acidic, or more alkaline, the soil becomes. An alkaline environment increases the speed of formation of calcium carbonate, the cementing molecules that form when dissolved calcium and carbon dioxide combine. These compounds are the same deposits that form water spots on bathroom tiles in areas that use so-called “hard” water.
These “cementor bugs,” as Nüsslein calls them, are ideal for creating cement because they can swim into virtually any microscopically small hole, resulting in a well-distributed network of cement bridges between sand particles and creating a strong block from formerly loose sand. “These bacteria can hold up buildings,” said Nüsslein. “Injecting these bugs and their food into sand could aid in solidifying foundations of buildings, making sandy soils more resistant to earthquakes, strengthening levees and bluffs and supporting dams.”
“The new method is quite useful after construction or on an existing building,” N?sslein added. “Compared with existing chemical techniques, there are no toxicity problems. The treatment does not change the structure of the soil, but only fills in some of the void spaces between grains.”
Nüsslein’s work was the subject of an international workshop funded by the National Science Foundation held in Boston this past April. The goal of this workshop was to bring together experts from engineering, geosciences, microbiology, oceanography and biology that are leaders in their field, to discuss the next steps for this new biogeoengineering technology.
Illustration from Time magazine
November 28, 2007.
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