Valencia: As Spanish microbiologist Pilar Bosch was casting around for a subject to investigate for her PhD in 2008, she stumbled across a paper suggesting that bacteria, her field, could be used in art restoration, her mother’s own area of expertise.

At that same moment, her mother – Pilar Roig, lecturer at the Heritage Restoration University Research Institute at the Polytechnic University of Valencia – was struggling to restore 18th-century paintings by Antonio Palomino in one of the oldest churches in Spain’s third-biggest city, Valencia.

She was finding it particularly difficult to remove glue that had been used to pull out the frescoes from the walls of the Church of Santos Juanes during restoration work in the 1960s.

“My mother had a very difficult problem to solve and I found a paper about bacteria used to clean frescoes in Italy,” Bosch, 42, said.

So she did her PhD on that project. And more than a decade later, daughter and mother have joined forces on a €4million ($6.4million) project, funded by local foundations, to use some of the techniques to restore the artworks in Valencia.

The microbiologist researcher trains bacteria by feeding them samples of the animal collagen glue that is stuck to the paintings. The bacteria then naturally produce enzymes to degrade the glue.

The family team then mixes the bacteria with a natural algae-based gel and spread it on the paintings, then nails them back on the walls, still covered in glue.

After three hours, the gel is removed, revealing glue-free paintings.