## 5 Conclusions  
The present research identified new species of fungi involved in the deterioration of mural paintings, and two consolidants used in restoration were assessed using microbiological and biochemical methods and colourimetry. They were isolated from deposited frescoes or from mural paintings from two Romanian monasteries. The fungal isolates contributed to deterioration through both biochemical ways--producing organic acids, hydrolytic enzymes and black pigments--and a mechanical way--stripping the pictorial layer or consolidant when the mycelium was removed. Experiments were performed with consolidants applied to an inert support and to fragments of frescoes treated with three different types of biocides, either applied to the surface or mixed with the consolidants. Finding that Paraloid(r) B72 and TDC treated with biocides were resistant to colonization by fungi encourages us to recommend them for use in consolidation because they can be expected to ensure the long-term conservation of restored mural paintings.  
The obtained results can be considered as a first attempt in an innovative research field that has two main goals: improving the resistance of consolidants to fungal colonization and long-term conservation of restored mural paintings. Experimental studies will be carried out to evaluate the properties of the consolidants after treatment with biocides and their compatibility with the pictorial layer.  
The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app12147229/sl](https://www.mdpi.com/article/10.3390/app12147229/sl)]([https://www.mdpi.com/article/10.3390/app12147229/sl](https://www.mdpi.com/article/10.3390/app12147229/sl)), Figure S1: Painted laboratory models before and after inoculation with Aspergillus sp. S1, Bipolaris sp. P2, Bipolaris sp. M3, Ulocdadium sp. H1, Bipolaris sp. M4, Bipolaris sp. M7. Figure S2: Experimental design to evaluate the resistance of consolidants with biocides integrated to fungal colonization. Figure S3: Experimental design to evaluate the resistance of consolidants with biocides integrated to fungal colonization. Figure S4:Identification of protease activity by plate assay method. Figure S5: Identification of esterase activity by plate assay method. Figure S6: Changes produced by fungi on the surface of consolidants. Figure S7: The effect of biocides applied on consolidants on the growth of Aspergillus sp. S1. Table S1: Calculated \(\Delta\)E for all treated areas. Table S2: Cleaning efficient percentage as calculated from the colorimetry data.  
Conceptualization, I.G., R.C., R.R. ([PERSON]) and L.G.; methodology I.G., R.C., R.R. ([PERSON]), S.N., M.D. and L.G.; formal analysis, M.E.; investigation, I.G., R.C., R.R. ([PERSON]), S.N., M.D., R.R. ([PERSON]) and L.G.; resources, I.G.; writing--original draft preparation, I.G., L.G., M.D., R.R. ([PERSON]), I.O. and R.C.; writing--review and editing, I.G., R.R. ([PERSON]), I.O. and R.C.; project administration, I.G.; funding acquisition, I.G. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI), grant number 570 PED/2020, and by the Romanian Academy, grant number RO1567-IBB05/2021.  
Not applicable.  
The data presented in this study are available on request from the corresponding authors.  
The authors declare no conflict of interest.