## 2 Results
### The Volatile Profile Allows the Separation of Malassezia Species and Growth Phases  
To identify volatile organic compounds (VOCs), we conducted headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS) in the exponential and stationary growth phases of the three species. We found 54 compounds, 40 annotated (Table 2). Annotations of each volatile were performed, assigning retention times and comparing the experimental mass spectra with theoretical retention indices and the NIST Mass Spectral Library. Fourteen compounds released by _Malassezia_ species were classified as unknown because it was impossible to make an accurate match of the experimental mass spectra with the NIST library or the compound was a possible isomer of other compounds, making it challenging to annotate them (Table 2). We isolated compounds detected in the mDixon media for further analysis. \begin{table}
\begin{tabular}{l c c c} \hline \hline  & _M. globosa_ & _M. restricta_ & _M. sympodialis_ \\ \hline Exponential phase & 30 h & 30 h & 10 h \\ Stationary phase & 90 h & 55 h & 35 h \\ \hline \hline \end{tabular} This table summarizes the specific times (presented in hours (h)) at which each phase occurs.  
\end{table} 
Table 1: Times of the exponential and stationary phases of _Malassezia_ according to the growth curve. Figure 1: Growth curve for _Malassezia_ species in mDixon broth. +++ ==ERROR: No output for this page==
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Na. **} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**CAS**} & \multirow{2}{*}{**H1**} & \multirow{2}{*}{**Bic**} & \multirow{2}{*}{**ClaserFax**} & \multicolumn{6}{c}{**M.globaea**} & \multicolumn{6}{c}{**M.centrica**} & \multicolumn{6}{c}{**M.spota**} \\ \cline{4-19}  &  
Most of the volatile classes identified belong to alcohols and polyols, fatty alcohols, alkanes, and unsaturated aliphatic hydrocarbons (Table 2). Each species has unique compounds in its volatile profile (Figure 2). For instance, _M. globosa_ produced six volatiles in both phases that were absent in the other species. Likewise, _M. restricta_ and _M. sympodialis_ released three differential compounds. In total, 29 compounds were shared by all species (Table 2, Figure 2). The total compounds characterized for each species with their corresponding identification number and the average percentage area, standard deviations, and the number of replicates in which each volatile was found are described in Table 2. The volatile compounds 3-propan-2-ylyclyclohexene, octan-3-one, octan-3-ol, and 2-ethylhexan-1-ol were identified only for _M. globosa_, and 2,3-dimethylcyclopent-2-en-1-one was identified only for _M. restricta_. Finally, (E)-oct-3-ene and (3E)-octa-1,3-diene were identified only for _M. sympodialis. M. globosa_, in the stationary phase, released more unique compounds, such as hept-2-en-1-ol, octan-3-ol, and 2-ethylhexan-1-ol (Table 2). Qualitative differences can be observed between all treatments where the abundance of compounds changes according to the species and the growth phase. The volatile profile emitted by the _Malassezia_ species discriminated by growth phases, including the reference of the volatile organic compounds (VOCs) from the control, is shown in Figure 3. Moreover, it is appropriate to note that most peaks and some of the largest peaks belonging to the culture medium were used as a control and not attributed to the _Malassezia_ species being examined. Unsupervised and supervised statistical analyses were performed to determine if the volatile profile allows for the separation of the three species tested. First, the 3D-principal component analysis (PCA) explained 45% of the variance observed in the volatile profiles of _Malassezia_ spp. For each species-growth phase, we plotted ellipses representing confidence intervals of 95% using a normal distribution to facilitate data interpretation.