A New Approach to Eliminate the Microorganisms Involved in the Deterioration of Stony Cultural Heritage by Biocides

The biodeterioration of cultural heritage is a worldwide phenomenon. It is closely linked to the presence of microorganisms such as bacteria, archaea, fungi, lichens, and their metabolites. Microbial colonization leads to physical and chemical damages as well as aesthetic changes of ancient objects. Biocides have been used for all kinds of cultural heritage material to control microbial growth as well as its deterioration. The present study focuses on applying current chemical biocides to improve conservation strategies of the cultural heritage and develops a way to reduce consumption of biocides to prevent the growth of microorganisms and reduce environmental biological damages.

In this study, the antimicrobial effects of commonly used biocides including benzalkonium chloride, isothiazolinone, formalin, glutaraldehyde, and active oxygen-based disinfectant powder were examined against bacteria and fungi isolated from Cyrus the Great tombstone by microdilution broth methods and the combined effect of biocides was studied by the microdilution chequerboard method.

Microdilution tests showed that glutaraldehyde and active oxygen-based disinfectant powder had higher MIC values than other biocides, benzalkonium chloride, isothiazolinone, formalin. On the other hand, other biocides were more effective against the tested bacteria.

The results of the study showed that all selected biocides had acceptable antimicrobial effects on microorganisms isolated from Cyrus the Great tombstone alone. When biocides were combined, they had a better antimicrobial effect resulting in less use of these materials.