## 3 Results
### Fermentation of Fish Waste
#### 3.2.4 Volatile Molecule Compounds
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Class of Compounds** & **Volatile Compound** & **Control** & **YL2** & **YL4** & **BSC** & **BSM** \\ \hline \multirow{5}{*}{} & 3-methyl-1-butanol & - & - & 0.09 & - & 3.16 \\ \cline{2-6}  & 1-pentanol & 0.07 & 0.09 & - & 0.07 & 0.25 \\ \cline{2-6}  & 2-penten-1-ol & 0.1 & - & 0.34 & - & 0.11 \\ \cline{2-6}  & 1-hexanol & - & - & - & - & 0.28 \\ \cline{2-6}  & 1-octen-3-ol & 0.77 & 0.83 & - & 0.51 & 0.93 \\ \cline{2-6}  & Benzyl alcohol & 0.1 & 0.05 & - & 0.07 & - \\ \cline{2-6}  & Phenyl ethanol & 2.11 & 0.19 & 0.14 & 0.11 & 3.46 \\ \hline Esters & Ethyl acetate & 0.22 & - & - & 0.06 & 0.4 \\ \cline{2-6}  & Acetic acid ethenyl ester & 0.4 & 0.29 & - & 0.16 & 0.42 \\ \cline{2-6}  & Tetradecanoic acid ethyl & 0.11 & - & - & 0.21 & 0.14 \\ \cline{2-6}  & ester & & & & & \\ \cline{2-6}  & Hexanoic acid ethylester & 0.13 & - & - & 0.2 & 0.2 \\ \hline Acids & Acetic acid & 11.84 & 2.16 & 4 & 5.23 & 15.92 \\ \cline{2-6}  & Propanoic acid & 0.13 & - & 0.24 & - & 0.28 \\ \cline{2-6}  & Octanoic acid & 0.32 & - & - & - & 0.16 \\ \cline{2-6}  & Decanoic acid & 0.41 & - & - & - & 0.24 \\ \hline Furans & 2-methylfuran & 0.15 & 1.26 & - & 1.48 & - \\ \cline{2-6}  & 2 -ethylfuran & 2.16 & 2.15 & 2.16 & 2.19 & 2 \\ \cline{2-6}  & Butylfuran & 0.04 & 0.05 & - & 0.03 & - \\ \cline{2-6}  & 2-methylfuran & 0.15 & 1.20 & 0.00 & 1.48 & 0.00 \\ \cline{2-6}  & 2-pentylfuran & 0.24 & - & 0.94 & - & 0.84 \\ \cline{2-6}  & 2-(2-pentenyl)furan & 1.77 & 3.66 & 1.53 & 4.31 & 3.06 \\ \cline{2-6}  & 2 -ethoxyfuran & 0.17 & 0.38 & 0.28 & 0.28 & - \\ \cline{2-6}  & 3-pentylfuran & - & - & - & 0.05 & - \\ \cline{2-6}  & 2-(2-propenyl)furan & 0.17 & 0.17 & - & - & - \\ \cline{2-6}  & 4-methyl-2 propylfuran & 0.62 & 0.62 & 0.54 & 0.65 & 0.46 \\ \hline Alkanes, alkenes, alkenes & hexadecane & 0.55 & 0.78 & 0.64 & 0.64 & 0.54 \\ \cline{2-6}  & 2,6,10,14 tetramethylpentadecane & 0.64 & 0.9 & 1.01 & 0.71 & 0.77 \\ \cline{2-6}  & 1,3-cyclooctadiene & 0.86 & 1.07 & 0.72 & 1.07 & 0.63 \\ \hline Heptadecane & 2.86 & 3.95 & 5.26 & 3.2 & 2.96 \\ \hline
1-pentadecene & 0.1 & 0.18 & 0.59 & 0.12 & - \\ \hline
2,4-dimethyl-1-heptene & - & - & - & - & 0.09 \\ \hline Decane & 0.06 & 0.06 & 0.04 & 0.05 & 0.08 \\ \hline
1,3-_cis_-5-_cis_-octatriene & 0.11 & 0.22 & - & - & - \\ \hline
1,3-_trans_-5-_cis_-octatriene & 0.07 & 0.15 & - & 0.16 & - \\ \hline
1-ethyl-1,4-cyclohexadiene & - & - & - & 0.11 & - \\ \hline \end{tabular}
\end{table} 
Table 3: _Cont._The control sample after fermentation was characterized by alcohols (16.4%), aldehydes (34.0%) and alkanes, alkenes and alkynes (21.3%) (Figure 4). The sample incubated with _B. amyloliquefaciens_, B5M, showed a higher abundance of alcohols (24.7%) and ketones (11.9%) compared to the control. The addition of both the two strains of _Y. lipolytica_ (YL2 and YL4) improved the abundance of aldehydes (50.6 and 53.8%, respectively) and reduced the content of acids (2.1 and 4.2 compared to 12.6%). Even B5C demonstrated a similar behavior to the two strains of yeast but to a lower extent. Analyzing these results with PCA (Figure 5), it was possible to observe that factor 1 explained 49.50% of the variance while factor 2 explained 27.64% of the variance. The control was in the fourth quadrant while all the other samples were distributed in the other three. The negative values characterizing PC1 were explained by aldehydes such as 2,4-heptadienal, benzaldehyde, 2-nonenal, 2-octenal and 2-butenal, wh  
Figure 4: Classes of compounds detected and identified in the samples of fish waste incubated with the selected microorganisms. YL4 and YL2 (_Y. lipolytica_), B5C (_B. subtilis_) and B5M (_B. amyloliquefaciens_). Results are expressed as relative abundance (%). Control: fish waste without any microorganisms.