# Eco-Friendly Preservation of Pharaonic Wooden Artifacts using Natural Green Products
## 3 Results
### Effect of Essential Oils (MICs) on Fungal Isolates and Chemical Composition  
The thyme, geranium, and cinnamon essential oils were the most effective against the fourteen deteriorating fungal species (Figures 1-3). The chemical composition of these essential oils was investigated by GC-MS (Supplementary Materials, Table S8), and the major constituents were identified. The thyme and geranium oils showed an MIC in the 0.25-1 uL/mL range. The antifungal activity of the thyme oil may be due to thymol (28.2%) and _p_-cymene (14.5%), being the main constituents. In the case of the geranium oil, the main components with antifungal activity were citronello1 (19.4%) and geraniol (36.8%). The cinnamon oil (MIC: 0.5-1 uL/mL) was third in the antifungal effectiveness ranking. The main constituents were eugenol (28.5%), cyanophyllene (16.3%), cinnamaldehydehyde (14.3%), and the acetic acid cinnamyl ester (12.8%). The five moderate EOs in the antimicrobial activity rankings were frank-incense oil (MIC: 0.5-2 uL/mL), lemongrass oil, menthe oil, tea tree oil, and eucalyptus oil. Lemongrass oil inhibited three fungal species (_Aspergillus niger, Rhizopus oryzae_, and _T. viridae_) at 0.5 uL/mL, whereas _A. flavus, A. fumigatus_, and _P. chrysogenum_ were the most resistant species, which were completely inhibited at 2 uL/mL. Menthe oil showed an MIC against fourteen deteriorating fungal species in the 0.5-4 uL/mL range. Tea tree oil  
Figure 1: The minimum inhibitory concentrations (MICs, uL/mL) of thyme, geranium, and cinnamon oils against the most deterioration-causing fungal species. The least significant differences (_p_\(<\) 0.05) were 2.51, 3.34, and 3.86 for the thyme, geranium, and cinnamon oils, respectively. Figure 2: The minimum inhibitory concentrations (MICs, uL/mL) of the frankincense, lemongrass, menthe, and tea tree oils against the most deterioration-causing fungal species. The least significant differences (_p_\(<\) 0.05) were 4.12, 5.42, and 5.84 for the frankincense, lemongrass, menthe, and tea tree oils, respectively. completely inhibited _A. terreus_ at 0.75 \(\mu\)L/mL. Eucalyptus (MIC: 1-8 \(\mu\)L/mL), roesmary (MIC: 1-8 \(\mu\)L/mL), and lavender (MIC: 2-8 \(\mu\)L/mL) were the oils with the lowest efficiency against the tested fungi. More details on MICs are reported in Supplementary Materials, Tables S3-S8. In the present study, thyme, geranium, and cinnamon proved to be the most effective EOs. They were selected to further investigate their effect on the cellulase, amylase, and protease activities of the four most frequent fungal species selected, which belonged to the _Aspergillus_ genus (_A. flavus, A. fumigatus, A. niger_, and _A. terreus_). The results are presented in Supplementary Materials, Tables S9-S11. A different inhibition was observed on the enzyme production of the four selected dominant fungal species with increasing concentrations (0.125, 0.25, 0.5, 0.75, 1 \(\mu\)L/mL) of the three tested EOs. In particular, thyme oil caused a complete inhibition of the cellulase productivity of _Aspergillus fumigatus_ and _A. terreus_ at 0.5 \(\mu\)L/mL, while productivity was fully inhibited for _A. flavus_ and _A. niger_ at 0.75 \(\mu\)L/mL. In the same way, fungal cellulase productivities were totally inhibited by geranium and cinnamon oil at 1 \(\mu\)L/mL, except for _A. terreus_, which was completely inhibited at 0.75 \(\mu\)L/mL, and _A. flavus_ and _A. terreus_ cellulase were reduced at 0.75 and 0.5 \(\mu\)L/mL, respectively. The amylase activity of _A. fumigatus_ and _A. terreus_ was completely inhibited by thyme oil at 0.5 \(\mu\)L/mL, while _A. flavus_ and _A. niger_ were fully suppressed at 0.75 \(\mu\)L/mL. Only the highest concentration (1 \(\mu\)L/mL) of geranium and cinnamon was necessary to completely inhibit the amylase activity of most species. Geranium oil fully inhibited the protease activity of _A. terreus_ at 0.75 \(\mu\)L/mL, while a concentration of 1 \(\mu\)L/mL totally inhibited the productivity of the other species. The protease activity of _A. flavus_ and _A.