Paper is a very useful information storage medium, but it is also somewhat delicious for microbes that can break it down as food, degrade the quality, and cause indelible stains and discoloration under the right conditions. Preventing this usually requires careful control, such as keeping humidity low, for storing paper for long periods.

In this study, scientists tested the ability of the bacterium Lysobacter enzymogenes to protect paper via the antifungal compounds it produces. This first required filtering out the pigments that the bacteria produced, to prevent them from discoloring the paper. Once a method for this filtering was in place, they found the bacterial culture supernatant could significantly reduce fungal growth on various kinds of paper, and protect the paper from staining and degradation.

Chen Z, Zou J, Chen B, Du L, Wang M. 2019. Protecting books from mold damage by decreasing paper bioreceptivity to fungal attack using de-coloured cell-free supernatant of Lysobacter enzymogenes C3. J Appl Microbiol 126:1772–1784.