## 2 Results and Discussion
### Volatile Organic Compounds (VOCs) after Fermentation
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Compound Name** & **RI (Calc.)** & **RI (Lit.)** & **R Match** & **Identification Method** \\ \hline
9 & 1-Hexanol & 1343 & 1355 & 832 & MS, RI \\
10 & 4-Methyl-2-heptanol & 1349 & 1372 & 900 & MS, RI \\
11 & 2-Octanol & 1410 & 1412 & 849 & MS, RI \\
12 & 2-Nonanol & 1508 & 1521 & 952 & MS, RI \\
13 & 1-Octanol & 1545 & 1557 & 912 & MS, RI \\
14 & 1-Nonanol & 1647 & 1660 & 883 & MS, RI \\
15 & 1-Decanol & 1751 & 1760 & 824 & MS, RI \\
16 & Citronellol & 1752 & 1765 & 801 & MS, RI \\
17 & Geraniol & 1833 & 1847 & 879 & MS, RI \\
18 & Benzyl alcohol & 1868 & 1870 & 924 & MS, RI \\
19 & Phenylethyl alcohol & 1904 & 1906 & 914 & MS, RI \\ \hline \multicolumn{5}{c}{Acids} \\ \hline
20 & Acetic acid & 1429 & 1449 & 946 & MS, RI \\
21 & Butanoic acid & 1620 & 1625 & 905 & MS, RI \\
22 & 2-Methyl butanoic acid & 1659 & 1662 & 929 & MS, RI \\
23 & 3-Methyl butanoic acid (isovaleric acid) & 1658 & 1666 & 956 & MS, RI \\
24 & Hexanoic acid & 1836 & 1846 & 903 & MS, RI \\
25 & Heptanoic acid & 1944 & 1950 & 864 & MS, RI \\
26 & Octanoic acid & 2049 & 2060 & 920 & MS, RI \\ \hline
27 & Nonanoic acid & 2154 & 2171 & 912 & MS, RI \\
28 & n-Decanoic acid & 2261 & 2276 & 801 & MS, RI \\ \hline \multicolumn{5}{c}{Esters} \\ \hline
29 & Ethyl acetate & 889 & 888 & 957 & MS, RI \\
30 & Butyl acetate & 1069 & 1074 & 959 & MS, RI \\
31 & 3-Methylbutyl acetate & 1120 & 1122 & 867 & MS, RI \\
32 & Ethyl hexanoate & 1230 & 1233 & 860 & MS, RI \\
33 & Ethyl heptanoate * & 1331 & 1331 & 771 & MS, RI \\
34 & 2-Phenylethyl acetate & 1813 & 1813 & 800 & MS, RI \\ \hline \multicolumn{5}{c}{Sulphur compounds} \\ \hline
35 & Methanethiol * & 690 & 692 & 734 & MS, RI \\
36 & Dimethyl disulphide & 1072 & 1077 & 965 & MS, RI \\
37 & Dimethyl trisulphide & 1386 & 1377 & 935 & MS, RI \\
38 & Methional & 1455 & 1454 & 809 & MS, RI \\
39 & 5-Ethenyl-4-methyl thiazole & 1527 & 1520 & 917 & MS, RI \\ \hline \multicolumn{5}{c}{Ketones} \\ \hline
40 & 4-Methyl-4-penten-2-one & 1069 & 1110 & 804 & MS, RI \\
41 & 2-Heptanone & 1183 & 1182 & 921 & MS, RI \\
42 & 2-Nonanone & 1390 & 1390 & 954 & MS, RI \\
43 & 2-Undecanone & 1600 & 1598 & 939 & MS, RI \\ \hline \multicolumn{5}{c}{Aldehydes} \\ \hline
44 & Benzaldehyde & 1530 & 1520 & 961 & MS, RI \\ \hline \multicolumn{5}{c}{Unknown compounds} \\ \hline
45 & Unknown 1 & 1027 & NA & \\
46 & Unknown 2 & 1139 & NA & \\
47 & Unknown 3 & 1181 & NA & \\
48 & Unknown 4 & 1597 & NA & \\
49 & Unknown 5 & 1803 & NA & \\ \hline \hline \end{tabular}  
* Identification method: MS—mass spectrum, RI—retention indices. *: co-eluted with air peaks/background compounds.  
\end{table} 
Table 3: _Cont._Figure 1: Heatmap visualisation and hierarchical clustering analysis of VOCs produced by LB672 based on the log 2 transformed average peak area of each VOC. Fermentation was carried out in the defined medium (DM) with 0.1% acetate added and supplemented with different amino acids separately or in combination (DMP: Phe added, DML: Leu added, DMI: Ile added, DM: defined medium, DMAA: Aamix added, DMM: Met added, DMT: Thr added, and DMG: Glu added). The green colour represents a higher abundance, whereas the red colour indicates a lower abundance. The VOCs represented in the heatmap are numbered according to the peak numbers (Table S1). Figure 2: Heatmap visualisation and hierarchical clustering analysis of VOCs produced by LB672 based on the log 2 transformed average peak area of each VOC. Fermentation was carried out in the defined medium (DM) with 1.2% acetate added and supplemented with different amino acids separately or in combination (DMAa: Aamix added, DMI: Ile added, DM: defined medium, DMM: Met added, DMP: Phe added, DML: Leu added, DMT: Thr added, and DMG: Glu added). The green colour represents a higher abundance, whereas the red colour indicates a lower abundance. The VOCs represented in the heatmap are numbered according to the peak numbers (Table S2).