Research has uncovered the culprit behind the calcification and subsequent hardening of lime, a phenomenon that has been blemishing many historic structures. The calcification process involves the deposition of lime. This occurs when rainwater permeates the stone structures, extracting the lime through joints in the basaltic rock. The leached lime then falls prey to specific bacteria, which transform it into a hard, calcified substance. The unfortunate consequence of this is a deterioration of the monument’s aesthetic appeal due to white, calcium carbonate deposits on its surface, which are exceptionally resistant to removal.
A striking example of this predicament is the Salabat Khan tomb, nestled 125 kilometres from Aurangabad in Maharashtra. This monument has lost much of its original beauty owing to these unsightly white residues.
The Bacteria Behind Monumental Damage
Comprehensive study conducted by the National Museum Institute of History of Art, Conservation, and Museology identified the bacterial species responsible for this damaging calcification process. They include Bacillus sp, Arthrobacter sp, Agromyces Indicus, and Aquamicrobium sp species.
Innovative Use of Bacterial Spray
The same study proposed an intriguing solution to this monument-degrading problem: a bacterial spray. This spray consists of the identified organisms combined with calcium carbonate, which can create a protective layer of calcite that helps to preserve monument exteriors.
This method works by spraying the micro-organisms evenly onto the monument’s surface and then nourishing them with a medium rich in calcium and urea. These fed bacteria work to induce carbonate precipitation by creating a less acidic environment and transforming the dissolved calcium into a defensive coating of calcium carbonate. This method is aptly termed biocoating.
Not only does this innovative technique clean monuments but it also safeguards them, potentially sealing any cracks without inflicting damage to the monument itself or its surface. This approach could replace the current method, which involves applying mud packs to marble surfaces of historical monuments – a process that can sometimes cause harm.
| Bacteria | Role in Calcification |
|---|---|
| Bacillus sp | Involved in converting leached lime into calcified substance |
| Arthrobacter sp | Plays a part in calcification and hardening of lime |
| Agromyces Indicus | Responsible for calcification process in limestone monuments |
| Aquamicrobium sp | Involved in the deposition of lime and subsequent bacterial action |
The National Museum Institute of History, Art, Conservation and Museology
The National Museum Institute of the History of Art, Conservation, and Museology was officially formed on January 27, 1989, under the Societies Registration Act, 1860. Headquartered in Delhi, this esteemed institution offers various courses of study, training, and research in several branches, including the history of art, museology, and conservation.
