When you think of art restorers at work, generally, you picture them with little brushes and chemicals, cleaning one square centimeter at a time. A very delicate and time-consuming task, as it often concerns centuries-old pieces of art, not only of great monetary value but also of great importance for the course of history. In Italy, art restorers at work are quite a common sight due to the enormous number of art present in the country. Yet even the Italians had to be shook when they learned about Michelangelo’s statues being cleaned by nothing else than microbes.
Of course, this story needs a bit of background info. It’s not like scientists just unleashed a number of arbitrary microbes on a bunch of centuries-old statues by one of Italy’s most famous artists. First of all, the little experiment took place in the Medici Chapel in Florence. The chapel was commissioned in 1520 by Cardinal Giulio de’ Medici, who asked Michelangelo to design an ornate family tomb. And so the artist did, not only designing the space itself but also sculptures depicting the Medici dukes Giuliano di Lorenzo and Lorenzo di Piero, four allegorical figures representing different times of day, and the Madonna and Child.
Alessandro de’ Medici’s liquids
Fast forward to 1595, when people started to notice the first stains and discolorations on the tomb. How they came there, no one knew back then. Yet now, almost half a century later, scientists know what went wrong. After the assassination of Alessandro de’ Medici in 1537, his body was almost dumped in the tomb, without the necessary ‘treatment’ (aka disembowelment). Leading his body to disintegrate in a not so distinguished way and, eventually, the liquids started to attack the marble. Even after a thorough restoration of the chapel which took place over the last decade, some of those stains simply wouldn’t disappear. Enter the microbes.
After an infrared spectroscopy by Italy’s National Research Council, which used infrared spectroscopy defined the stains, Anna Rosa Sprocati, a biologist at the Italian National Agency for New Technologies, stepped in. Together with her team they selected eight strains of bacteria out of a collection of 1.000 of those strains. Those bacteria, which were chosen for their gentle approach, eventually got rid of the stains. “It’s better for our health, for the environment, and the works of art”, as Daniela Manna, one of the art restorers, told The New York Times. Or how a couple of bacteria consumed the unwanted remnants of duke Alessandro de’ Medici.