For thousands of years, humanity has carved its history into stone, but today, our irreplaceable cultural heritage is decaying from severe weathering.

To save them, we traditionally spray these stones with chemicals. But here is the problem: these chemicals are often toxic, expensive, or actually trap moisture inside the stone, causing it to decay from the inside out. Even newer “green” methods that use bacteria are unpredictable and release harmful chemicals into the air, such as ammonia.

Our project solves this by growing a natural, protective shield directly on the stone. We are developing a safe, eco-friendly biotechnology that mimics nature to rebuild the stone from within, without any toxic side effects. In fact, while naturally occurring cyanobacteria (photosynthetic microorganisms) consumes carbon dioxide from the environment, stable minerals are produced to restore the gaps on the stone surface. This process called bioconsolidation, can be a predictable, reliable formula used on historical sites anywhere in the world, safeguarding our shared human history so it survives for generations to come.

The project CYA-TECH, aims to develop a CYAnobacteria-based consolidation TECHnology for the conservation of stone heritage through bioprotection strategies. CYA–TECH is hosted in a major global cultural hub, the city of Milan. It has a rich history in art and architecture and its home for the “Duomo di Milano”, the massive Gothic cathedral in the heart of the city. This architectural masterpiece is the perfect example of the outdoor stone heritage the project was designed to protect.

Represented by the magnificent “Duomo di Milano”, we show the two faces of cultural heritage: on the right, the beautiful facade of the stone heritage that citizens of the world can appreciate; and on the left, the deterioration and weathering, a harsh reality for stone heritage displayed outside in the environment.

This agar art represents made with cyanobacteria (green pigment: chlorophyll) is part of CYA–TECH’s initiative to move towards the conservation of these monuments with green, sustainable, efficient, and durable strategies using microorganisms that are beneficial for the environment, the users and the stone. Irreplaceable cultural and historical assets are under threat of the environment but could be given new life with the aid of cyanobacterial biomineralization or by using bioprotective cyanobacterial biofilms. By these means, the aesthetic integrity and durability of stone monuments will survive for future generations.