# FTIR Spectroscopy for Identification and Intra-Species Characterization of _Serpula Iacrymans_
## 4 Discussion
studied 722 unknown yeast isolates with a library of reference spectra based on 332 strains belonging to 18 genera and 74 species and obtained a correct identification rate of 97.5% [38]. In a study analysing 25 mould strains with a reference spectra library based on 106 strains belonging to 14 genera and 32 species, the correct identification rates of 98.97% and 98.77% were obtained at the genus and species level, respectively [19]. In another study of 105 strains, with a reference spectra library based on 288 strains belonging to 26 genera and 68 species, the correct identification rates of 99.17% and 92.3% were obtained at genus and species level, respectively [20]. In the conclusion of the present study, the most efficient fungal sample preparation and analysis protocol to identify an isolate suspected to be _S. lacrymans_ is a culture on the surface of a filtration membrane deposited on a malt extract agar medium; a collection of the mycelium by scraping, followed by drying of the mycelium by heat treatment; FTIR analysis; the processing of the spectral data by vector normalisation, and PLS-DA statistical analysis. The constitution of a library of reference spectra based on a larger number of strains of _S. lacrymans_ and other fungi and the analysis of field isolates of wood-decay fungi (particularly brown-rot fungi such as _Gloeophyllum sepiarium, Fibroporia (Antrodia) vaillantii, Contiophora puteana, Serpula himantoides_) is necessary to confirm the effectiveness of this protocol. The next step in this study is to adapt the use of FTIR spectroscopy to the identification of _S. lacrymans_ by direct in situ analysis without fungal culture. This will involve performing FTIR spectra of fungi after growth on different native substrates such as wood, and materials found in buildings. The following are available online at [[https://www.mdpi.com/article/10.3390/app11188463/s1](https://www.mdpi.com/article/10.3390/app11188463/s1)]([https://www.mdpi.com/article/10.3390/app11188463/s1](https://www.mdpi.com/article/10.3390/app11188463/s1)), Figure S1: FTIR spectra of fungi obtained after growth under different conditions, from different sample preparations, and two normalisations of the spectral data. Figure S2: FTIR spectra of fungi obtained after growth in different conditions illustrating the reproducibility of the method and the heterogeneity of the mycelial matter. Conceptualization, P.D.M. and F.B. ; methodology, P.D.M. ; validation, P.D.M. and F.B. ; investigation, R.B. ; data curation, R.B. ; writing-original draft preparation, P.D.M. ; writing-review and editing, R.B. and F.B. ; supervision, P.D.M. ; project administration, P.D.M. ; funding acquisition, P.D.M. and F.B. All authors have read and agreed to the published version of the manuscript. **Funding:** This study was part of the project \"Biodeterioration du bois dans les batiments historiques: biodiversite microbiome et evaluation in vitro de traitements alternatifs\" funded by \"La Fondation des Sciences du Patrimoine\", LabEx PATRIMA (AAP_2016_01), Agence nationale de la recherche ANR-10-LABX-0094-01. **Conflicts of Interest:** The authors declare no conflict of interest.