Table 3.
Summary of the detected surfactin lipopeptides extracted from cultures of B. amyloliquefaciens ST34, as detected using high resolution mass spectrometry (<10 ppm)
| Surfactin group (Abbr) | UPLC Rt (min)a | Characterised and proposed* peptide sequences in surfactin group | Mono-isotopic Exp/Theor M r | Protonated specie Exp/Theor m/z | Sodiated specie Exp/Theor m/z |
|---|---|---|---|---|---|
| Surfactin 1 (Srf1) | 10.6; 11.2 | Cyclo[(C
13
H
24
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Val] Cyclo[(C 13 H 24 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Val] |
993.6376 993.6403 |
994.6472 994.6481 |
1016.6265 1016.6190 |
| Surfactin 2 (Srf2) | 11.0; 11.2; 11.9 | Cyclo[(C
14
H
26
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Val] Cyclo[(C 14 H 26 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Val] |
1007.6521 1007.6552 |
1008.6604 1008.6596 |
1030.6350 1030.6328 |
| Cyclo-[(C
13
H
24
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] Cyclo[(C 13 H 24 O 2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] *Cyclo-[(C 13 H 24 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] *Cyclo-[(C 13 H 24 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] | |||||
| Surfactin 3 (Srf3) | 11.6; 11.7; 12.3 | Cyclo[(C
15
H
28
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Val] Cyclo[(C 15 H 28 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Val] |
1021.6693 1021.6715 |
1022.6780 1022.6752 |
1044.6586 1044.6494 |
| Cyclo[(C
14
H
26
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] Cyclo[(C 14 H 26 O 2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] *Cyclo-[(C 14 H 26 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] *Cyclo-[(C 14 H 26 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] | |||||
| Surfactin 4 (Srf4) | 12.1; 12.2 | Cyclo[(C
15
H
28
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] Cyclo[(C 15 H 28 O 2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] *Cyclo[(C 15 H 28 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] Cyclo[(C 15 H 28 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] |
1035.6819 1035.6881 |
1036.6902 1036.6909 |
1058.6718 1058.6662 |
| Surfactin 5 (Srf5) | 12.6; 12.7 | Cyclo[(C
16
H
30
O
2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] *Cyclo[(C 16 H 30 O 2)-L-Glu-L-Leu-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] *Cyclo[(C 16 H 30 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Leu] *Cyclo[(C 16 H 30 O 2)-L-Glu-L-Ile-D-Leu-L-Val-L-Asp-L-Leu-L-Ile] |
1049.6992 1049.7032 |
1050.7120 1050.7066 |
1072.6926 1072.6886 |
Their proposed chemical structures, theoretical (Theor) and experimental (Exp) M r and monoisotopic m/z values, as well as observed UPLC retention times for representative examples are provided
a UPLC retention time of main peaks corresponding to the group’s m/z value