Metabolomics and metagenomics characteristic of historic beeswax seals

The aim of the study was to determine microbial and metabolites diversity on the samples of damaged mediaeval beeswax seals from the Archdiocese Archive of Gniezno, Poland. We employed high-throughput sequencing on the Illumina platform and Ag-109 SALDI metabolome analysis for the first time to assess biodeterioration of the beeswax seals. Bacteria belonged to the genera Mesorhizobium, Delftia, Ralstonia, Burkholderia, Stenotrophomonas, Olsenella and fungi: Aspergillus, Penicillium, Aureobasidium, Chaetomium, Malassezia, and others microorganisms identified with lower relative abundance may be responsible for the biodeterioration of the seals analysed. Between 112 and 456 chemical compounds were identified on the seal samples. In all samples, fatty acids, monodi- and triglycerides, hydrocarbons and lipids including glycerophosphocholines, glycerophosphoethanolamines, glycerophosphoserines, glycerophosphoglycerols, glycerophosphates, glycerophosphoinositols, ceramides and sphingomyelins, were detected. Chemical compounds including fatty oxyacids and metabolites of microbiological origin belonged to 20 metabolic pathways can be considered as indicators of biodeterioration of beeswax seals. The usefulness of new available methods - high-throughput sequencing on the Illumina platform and Ag-109 SALDI in historical seals biodeterioration analysis was demonstrated.