Microbial Diversity of Biodeteriorated Limestone Cultural Heritage Assets Identified Using Molecular Approaches—A Literature Review

A significant part of our stone heritage is made of limestone. Researchers are increasingly concerned about the risk of biodeterioration of these important objects. In this article, we present an up-to-date review of the microbial diversity of biodeteriorated limestone cultural heritage (CHL). This is based on an extensive bibliographic search of the literature investigating biodiversity using culture-dependent (CD) and culture-independent (CI) techniques. In the case of the former, only articles in which microorganisms were identified using molecular tools that generate DNA sequences were selected, with the aim of providing traceable identification based on the sequences submitted to public databases. The literature search resulted in the selection of 50 articles published between 2004 and 2023. The biodiversity data obtained from the CHL were organized into the following groups: fungi (626 records), bacteria and cyanobacteria (786 and 103 records, respectively), algae (51 records), and archaea (27 records). Within each group, the microbial diversity studied was compared according to results obtained using CD and CI techniques. Of all the articles selected, 12 used both approaches, demonstrating the growing effort to discover the total microbiome of biodeteriorated cultural heritage assets.