Construction of a high-efficiency, batch-stable artificial essential oil blend for sustainable biodeterioration control of cultural heritages

Natural plant essential oils (EOs) are promising green biocides for cultural heritage preservation, but batch variability limits standardized use. Here, we developed a composition-defined artificial essential oil (AEO) blend for reliable biodeterioration control. GC/Q-TOF fingerprinting linked EO antimicrobial performance to enrichment of core active molecules rather than overall chemical diversity. Checkerboard assays and mixture response surface methodology identified an optimized formula of 65% carvacrol, 15% cinnamaldehyde, 10% linalool/nerol, and 10% eugenol. The AEO showed strong synergistic activity against Bacillus subtilis and Aspergillus niger. Mechanistic assays indicated rapid microbial inactivation through membrane disruption, intracellular leakage, ATP depletion, and inhibition of key metabolic enzymes. Field spray observations with the diluted microemulsion provided preliminary evidence of reduced visible biodeterioration and delayed recolonization for more than six months under monitored site conditions, with no obvious appearance change in photographic comparisons. This standardized formulation offers a controllable strategy for heritage biodeterioration management.