Scientists in Costa Rica have found some new species of fungi thriving in an odd place: on a collection of lithographs by 19th-century French artist Bernard Romain Julien. The microorganisms are speeding the degradation of the printed artworks, which are among the oldest items in the University of Costa Rica's art collection and were acquired as a tool to teach drawing techniques.

To preserve the lithographs, Geraldine Conejo-Barboza, a researcher at the university's chemistry department and its Institute of Art Research, and her colleagues are developing a spray that could eliminate or slow the fungi's growth and stop natural acidification processes that are destroying the artwork. “Our idea is to take the biomolecule hydroxyapatite, which has been reported to improve the acidity of paper, and develop a hybrid [molecule] that can also eliminate the fungi,” Conejo-Barboza says. She plans to add zinc oxide and zinc ions to the molecule's surface to act as antifungal agents.

Before applying a medicine, however, one must identify the disease. To find out what microbes are attacking the artwork, Max Chavarría, a molecular biologist at Costa Rica's National Center for Biotechnological Innovation, studied 20 out of more than 1,000 lithographs in the collection. He extracted 21 fungi samples, two of which were unknown to science. “It was a surprise to find two new species in such a limited environment,” Chavarría says. The discovered species, Periconia epilithographicola and Coniochaeta cipronana, were described in May in Scientific Reports.

Conejo-Barboza has already synthesized a few fungi-fighting products that she aims to test in the laboratory. Salomón Chaves, subdirector of the Institute of Research in Art, has spent the past five years restoring the lithographs. The new product has the advantage of being a spray, he says. Protecting paper from acidification currently requires bathing it in alkaline substances and then carefully drying it—which can shrink the paper if not done correctly. The researchers hope the new chemicals will fight the microbes and acidification effectively and prove useful for preserving collections elsewhere.

Such fungi are not all bad, however: their ability to degrade cellulose—a tough substance found in plant cell walls—could be useful for treating agricultural waste from crops such as pineapple, coffee and sugarcane.