Origin and Control Strategies of Biofilms in the Cultural Heritage

Abstract

Biodeterioration is defined as the undesirable change in the properties of materials caused by the activity of biological agents. This process is complex and involves alterations in the physicochemical and mechanical properties by the action of organisms and depends on the microorganisms involved, type of substrate, and environmental conditions. The biodeterioration of cultural heritage is the physical or chemical damage caused by microorganisms on objects, monuments, or buildings that belong to the cultural heritage. Among the main materials that can be affected are: stone, metal, ceramic, polymers, and other materials. Among the main undesirable effects to these materials are: discoloration, dissolution, rupture, and efflorescence among others. Biofilms represent the usual form of growth of bacteria and consist of communities of microorganisms that grow attached to an inert surface or a living tissue, surrounded by an extracellular matrix that they themselves synthesize. The importance of biodeterioration by biofilms is mainly related to changes in pH values, ionic concentrations, oxide-reduction reactions in the biofilm thickness, and in the interface with the substrate and enzymatic degradation. This chapter presents evidence of the participation of biofilms and associated mechanisms in biodeterioration as well as the main prevention and control strategies.

Nanopore Sequencing and Bioinformatics for Rapidly Identifying Cultural Heritage Spoilage Microorganisms

“…Moreover, among the isolated bacteria, K. rhizophila IP5, B. licheniformis IP7, and S. maltophilia IP9 were able to form biofilm. This bacterial aggregation is the main cause of biodeterioration, since microorganisms can resist adverse abiotic conditions and many biocides and are also able to deteriorate manufactures (Stewart, 2002;Dakal and Cameotra, 2012;Rivera et al, 2018). This was confirmed by the antibiotic susceptibility test that revealed several resistances for the different strains; indeed, it has been reported that some resistance mechanisms are common to both biocides and antibiotics (Scientific Committee on Emerging and Newly Identified Health Risks [SCENIHR], 2009).…”

“…Indeed, it is known that the biodeterioration process can be due to the production of inorganic acids like nitrous and nitric acid and salts like nitrite and nitrate by nitrifying bacteria (Mansch and Bock, 1998). Therefore, the results of FTIR analysis, which highlighted the presence of nitrate residues and gypsum on salt efflorescences, strongly correlate with metabolism of Bacillus, Kocuria, and Paenibacillus species isolated from the hypogeum wall (Laiz et al, 2000;Castrillón Rivera et al, 2019) (Figure 4). In agreement, at high humidity, soluble calcium carbonate is transformed into calcium sulfate, namely gypsum, causing visible salt efflorescence (Atlas et al, 1988).…”

“…While many of them were reported to be involved in the formation of salt efflorescences such as the genera of Bacillus, Kocuria, Paenibacillus, and Arthrobacter (Laiz et al, 2000), Pseudomonas spp. resulted as being involved in calcite production (Rivera et al, 2018). Among the isolates, three strains were chosen as representatives to be further characterized, as they belong to the Gram-positive P. pabuli, K. rhizophila, and B. licheniformis and one to the Gram-negative S. maltophilia species.…”

“…Salts deposited are composed of a variety of different chemical compounds, including carbonates, chlorides, nitrates, and sulfates. Salt efflorescences can be observed in environments with high levels of humidity, where they are generated by the action of nitrifying bacteria that convert the organic compounds into nitrate salts (Castrillón Rivera et al, 2019). Thus, studying these efflorescences could provide a means for identifying at least the type of microorganisms that are spoiling that specific CH.…”

Effects of the Ionizing Radiation Disinfection Treatment on Historical Leather

“…The biodegradation of cultural heritage is mainly caused by the ability of microorganisms to form biofilms (Rivera et al, 2018). Indeed, bacteria can aggregate and adhere to a surface, forming a group of cells producing an extracellular matrix composed of DNA, proteins and polysaccharides.…”