Biocement for Sandcastles

A bacterial species could be an important tool used to restore historical buildings in the future, thanks to a PhD project underway at Murdoch University.

Now in the third year of her PhD, Vicky Whiffin has been testing the ability of a bacterial species to convert sand into limestone.

"This bacterium uses an enzyme to make its surroundings less acidic, which is a good environment for them to grow", said Ms Whiffin.

"The by-product of this reaction is calcium carbonate, or limestone."

Ms Whiffin has developed a way to harness this ability to make rock, and can now convert beach sand castles into take-home sandstone castles.

"Cement is currently used for a lot of restoration work, but water can build up behind it and cause it to crumble away," she said.

"This new biological system allows the water to leach out, which makes it a more secure option than concrete for mending heritage structures."

Ms Whiffin believes her biotechnology work will have many applications, not only for restoring historical buildings, but also mine shafts and other industrial structures.

Recently a Dutch company responded to Ms Whiffin's website and shipped sand samples from Holland for testing.

They were impressed by the capability of the bacteria to cement sand samples from Dutch dykes that protect the land from rising sea levels.

Currently pilot scale field trials are being designed to test this technology on dykes.

"We have not yet investigated the full range of possibilities for the technology, but we believe it will have very broad applications," said Ms Whiffin.

"In fact, a similar technique is being used to clean up strontium spills in the United States at the moment."

The project, supervised by Dr Ralf Cord-Ruwisch from Murdoch University and Dr Ed Kucharski from Lithic Technology, has aimed to mimic the

natural formation of limestone in a more controlled way.

This project is one of a number of industry supported environmental biotechnology projects at Murdoch University.

Murdoch's expertise in this area has helped in a bid for a Cooperative Research Centre in environmental biotechnology.

More information on biocement can be found at http://wwwstaff.murdoch.edu.au/~vwhiffin/biocement.html