The microbiome of candle beeswax drops on ancient manuscripts

Many ancient manuscripts are littered with wax drippings from the candles used while writing or reading them. Bacterial and fungal species associated with the wax in a manuscript containing an unusually large number of wax drops were analysed by metabarcoding with Oxford Nanopore Sequencing (MinION). In addition, culturable fungi and bacteria were isolated from the wax and tested for enzyme activities. The mechanism of colonisation of wax drops by airborne microorganisms was also reproduced. Imaging by electron microscopy showed the presence of mycelium and fungal fruiting structures on the wax particles. Wax is not a substance whose addition makes the paper more biodegradable, as the colonisation experiment conducted in this study has shown. However, the microanalysis highlighted that the drops represented points of accumulation of dust and material eroded from the pages that acted as nutritional hotspots for the development of a particular assemblage of microbial species.