Bacteria cause old buildings to feel off-color

October 27, 2008

The assumption that time, weather, and pollution are what cause buildings to decline is only partly true. Bacteria are also responsible for the ageing of buildings and monuments – a process known as biodeterioration, where organisms change the properties of materials through their vital activities. Leonila Laiz from the Institute for Natural Resources and Agrobiology in Seville, Spain, and colleagues have just isolated five new strains of bacteria that degrade old buildings. Their work1 is published online this week in Springer's journal Naturwissenschaften.

Over the last decade, both microbiologists and conservators have been studying the microbial colonization and biodeterioration of both mural paintings in ancient monuments and plaster walls in churches. A specific family of bacteria, Rubrobacter, is commonly found in aged monuments and is thought to be responsible for their rosy discoloration. Until now, only three Rubrobacter species have been identified, and they all thrive in high temperatures of 45 to 80 degrees Celsius (thermophilic bacteria).

Laiz and her team studied three indoor sites showing overt biodeterioration: the Servilia and Postumio tombs in the Roman Necropolis of Carmona in Spain and the Vilar de Frades church in Portugal. Their microbiological and molecular analyses identified five new Rubrobacter strains. The strains are partly involved in the process of efflorescence formation, where salt residues form on buildings, due to the loss of water after exposure to air for a prolonged period of time. Efflorescences lead to damage in the porous structure of the rocks and the gradual deterioration of these buildings.

Two of the newly isolated strains were then grown onto rocks to replicate the biodeterioration process in the laboratory. The Rubrobacter cells penetrated the mineral matrix and crystals formed in contact with the bacterial film. When the film separated from the rock surface after exposure to heat, it removed mineral grains, producing a mechanical deterioration. These three processes are characteristic of biodeterioration and confirm that the isolated bacteria are actively involved in the ageing of the studied buildings.

This study of new Rubrobacter that thrive at lower temperatures (non-thermophilic bacteria) gives another insight into the physiology and activity of these bacteria present in monuments.

Citation: Laiz L et al (2008). Isolation of five Rubrobacter strains from biodeteriorated monuments. Naturwissenschaften DOI 10.1007/s00114-008-0452-2

Source: Springer

Related Stories

Recommended for you

Microsoft describes hard-to-mimic authentication gesture

August 1, 2015

Photos. Messages. Bank account codes. And so much more—sit on a person's mobile device, and the question is, how to secure them without having to depend on lengthy password codes of letters and numbers. Vendors promoting ...

Netherlands bank customers can get vocal on payments

August 1, 2015

Are some people fed up with remembering and using passwords and PINs to make it though the day? Those who have had enough would prefer to do without them. For mobile tasks that involve banking, though, it is obvious that ...

How bees naturally vaccinate their babies

July 31, 2015

When it comes to vaccinating their babies, bees don't have a choice—they naturally immunize their offspring against specific diseases found in their environments. And now for the first time, scientists have discovered how ...

Model shows how surge in wealth inequality may be reversed

July 30, 2015

(Phys.org)—For many Americans, the single biggest problem facing the country is the growing wealth inequality. Based on income tax data, wealth inequality in the US has steadily increased since the mid-1980s, with the top ...

A cataclysmic event of a certain age

July 27, 2015

At the end of the Pleistocene period, approximately 12,800 years ago—give or take a few centuries—a cosmic impact triggered an abrupt cooling episode that earth scientists refer to as the Younger Dryas.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.