Extreme Colonizers and Rapid Profiteers: The Challenging World of Microorganisms That Attack Paper and Parchment

Microorganisms form the backbone of life on Earth. Over billions ofyears, they have colonized and shaped every possible niche on the planet. Microbeshave modelled both the land and the sea, and have created favourable conditions formulticellular organisms to thrive in. Our understanding of how microbial diversity isdistributed across natural environments and how microbes affect ecosystems isconstantly evolving as public databases are set up and new techniques based onmassive sequencing are developed. The microbiome found in a particular anthropogenic environment is generally much less complex than those found in natural ones:there is less competition and the main actors are often linked to survival mechanismsregulated by a few limiting factors. Despite this simplicity, it is very difficult to linkcause and effect when seeking to identify the role of individual organisms. In thecase of biodeterioration of paper and parchment, even when analysing the individualcomponents of a simple phenomenon, it is not always easy to understand themechanisms at play. Works of art are unique objects and the elements that determinethe arrival and establishment of one or more microorganisms and the direction thatthe biodeterioration process takes are always different. In some cases, however, thereare common denominators and predictable mechanisms. The variables that comeinto play are examined below.