If you live near the ocean, chances are high that your home is built over sandy soil. For example many places in San Francisco are built on sandy soil or fill. Many homes built on this type of soil were badly damaged during the 1989 Loma Prieta earthquake.
When an earthquake strikes, deep and sandy soils can turn to liquid by a process known as liquefaction, with disastrous consequences for the buildings above. In an odd application of biotech, researchers at UC Davis have found a way to use bacteria to steady buildings against earthquakes by turning these sandy soils into rocks.
“Starting from a sand pile, you turn it back into sandstone,” the chief researcher explained. It is already possible to inject chemicals into the ground to reinforce it, but this technique can have toxic effects on soil and water. In contrast, the use of common bacteria to “cement” sands has no harmful effects on the environment. The new process, so far tested only at a laboratory scale, takes advantage of a natural soil bacterium, Bacillus pasteurii. The microbe causes calcite (calcium carbonate) to be deposited around sand grains, cementing them together.
So far this method is limited to labs and the researchers are working on scaling their technique.
Below: Before and After electron micrographs of microbiollogically-induced calcite precipitation in which B. pasteurii cells are embedded.