Biorestoration - Tamarit Rehabilitations

A little-known aspect of the protection and conservation of historical heritage is the use of bacteria for the restoration of historical monuments and buildings. This innovative technique, known as bio-restoration, uses micro-organisms to clean and repair structures damaged by factors such as pollution, ageing and natural wear and tear.

Scientists discovered that certain bacteria can produce minerals that consolidate stone and repair microscopic cracks. In addition, some bacteria are able to remove harmful deposits without affecting the integrity of the original material. This technique is particularly useful in the restoration of works of art and architecture in limestone and marble, where traditional chemical or mechanical methods could cause more harm than good.

This biotechnological approach is not only more sustainable and respectful of historical materials, but also represents a significant advance in conservation science, opening up new possibilities for the preservation of our cultural heritage with less invasive and more environmentally friendly methods.

Bacteria used in the bio-restoration of historical heritage represent an innovative and sustainable tool for the conservation of monuments and buildings. old buildings. Here I explain in detail how these bacteria work, their application and the times of action:

Types of Bacteria Used

The most commonly used bacteria in biorestoration belong to the following genera Bacillus, Pseudomonas y Desulfovibrio. These bacteria are selected for their ability to precipitate calcium carbonate (CaCO3), which helps to consolidate and repair structures or their ability to break down organic and inorganic contaminants without damaging the original substrate.

Mechanisms for Action

1. Calcium Carbonate Precipitation:
   • Bacteria precipitate calcium carbonate by metabolising certain compounds in a process known as biomineralisation.
   • Calcium carbonate is deposited in the cracks and pores of the stone, helping to consolidate the structure and repair small cracks.
2. Pollutant Decomposition:
   • Some bacteria can break down organic and inorganic contaminants, such as sulphates and nitrates, which damage stone surfaces.
   • These bacteria metabolise pollutants and transform them into products that are less aggressive to the stone.

Application Process

1. Identification of the problem:
2. Bacterial Culture Preparation:
   • Bacteria are grown in the laboratory under controlled conditions until the amount required for treatment is reached.
3. Application:
   • The bacteria are applied to the surface of the monument using various techniques, such as spraying, crevice injection or by means of pastes and gels containing the micro-organisms.
   • In some cases, biofilms, which are thin layers of bacteria immobilised in a matrix that adhere to the surface of the material to be restored, can be used.
4. Monitoring and Maintenance:
   • After application, bacterial activity and its effect on the stone is monitored. This monitoring may include chemical and physical analysis to assess the consolidation and cleanliness of the surface.
   • In some cases, it may be necessary to reapply the bacteria or adjust the environmental conditions to optimise bio-restoration.

Performance Times

• Short Term (weeks to months):
  • Bacteria start to act quickly, with visible effects on the cleaning of surfaces and the initial consolidation of materials.
  • During this time, it is essential to monitor progress and adjust treatment as needed.
• Medium Term (months to one year):
  • The consolidation of the stone through the precipitation of calcium carbonate becomes more evident, and the damaged structures show a marked improvement.
  • The bacteria continue to metabolise pollutants, reducing the amount of harmful substances on the treated surface.
• Long-term (several years):
  • The success of bacterial treatment can last for several years, especially if regular maintenance is carried out and environmental conditions are controlled.
  • In many cases, bio-restoration can significantly reduce the need for future interventions, extending the lifespan of the historic heritage.

Advantages and Limitations

Advantages:

• Sustainability: Use of natural and non-invasive methods.
• Effectiveness: Ability to reach areas that are difficult to treat with traditional methods.
• Preservation: Minimises additional damage to historic structures.

Limitations:

• Environmental conditions: Bacteria require specific humidity and temperature conditions to be effective.
• Time: Biological processes can be slower compared to chemical methods.
• Monitoring: Need for continuous monitoring to ensure effectiveness of treatment.

Case Studies

A notable example is the use of Bacillus cereus in the restoration of the convent of San Agustin in Salamanca, Spain. The bacteria were used to precipitate calcium carbonate and consolidate the sandstone surfaces, achieving a successful restoration without damaging the original material.

Bio-restoration is a growing field which combines biotechnology and heritage conservationWe offer innovative and environmentally friendly solutions for the preservation of our cultural history.