## 2 Diversity of LPBSs and NRPSs from _Bacillus_ and _Pseudomonas_
### Bacillus
#### 2.1.1 Surfactin and Lichenysin Synthetases  
Surfactin and lichenysin are structurally related LPBSs produced by _B. subtilis_ and _B. licheniformis_[3, 7, 21]. Several other forms of surfactin with amino acid variation at position 2, 4, and 7 have been reported [22]. Surfactin carries strong surfactant properties by reducing the surface tension of water from 72 to 27 mN/m at a critical micelle concentration (CMC) of 25-220 mg/L depending on its variants and determined conditions [3, 23]. A surfactin-like compound termed lichenysin is at least a 2-fold more efficient biosurfactant than surfactin, probably due to the replacement of Glu1 by Gln1 [6, 23]. Surfactin was first identified as an inhibitor of fibrin clot formation. It also exhibits anti-microbial, anti-tumor, anti-viral, and hemolytic properties [24]. Surfactin is required for the biofilm formation of producing cells [25, 26], swarming motility [27, 28], and fruiting body formation [29]. However, surfactin also inhibits biofilm formation of other bacteria by interfering with attachment of the cells to surfaces [30]. These LPBSs are usually a mixture of compounds with different lengths and types of fatty acid (FA), \(\beta\)-hydroxy FA (FA-\(\beta\)-OH), \(\beta\)-amino FA (FA-\(\beta\)-NH\({}_{2}\)) or guanidylated-\(\beta\)-OH FA (\(g\)FA-\(\beta\)-OH). The \(\beta\)-OH or \(\beta\)-NH\({}_{2}\) group of FA forms an ester or peptide bond with the carboxyl group of the \(C\)-terminal amino acid. For fengycin, circulocins, fusaricidin, and kurstakin, the carboxyl group of the \(C\)-terminal amino acid is lactonised with the hydroxyl group of Tyr\({}_{3}\), Thr\({}_{1}\), Thr\({}_{1}\), and Ser\({}_{4}\), respectively. \begin{table}
\begin{tabular}{l l l} \hline \multicolumn{1}{c}{**Name**} & \multicolumn{1}{c}{**Structure**} & \multicolumn{1}{c}{**Ref.**} \\ \hline
**Surfactin family** & & \\ Surfactin & FA-\(\beta\)-OH-l-Glu-l-Leu-d-Leu-l-Val-l-Asp-D-Leu-l-Leu & [31] \\ Lichenysin A/D & FA-\(\beta\)-OH-l-Gln-l-Leu-d-Leu-l-Val-l-Asp-d-Leu-l-Ile & [7,32] \\ (Lichenysin B) & FA-\(\beta\)-OH-l-Glu-l-Leu-d-Leu-l-Val-l-Asp-D-Leu-l-Leu & [33] \\ (Lichenysin C) & FA-\(\beta\)-OH-l-Glu-l-Leu-d-Leu-l-Val-l-Asp-d-Leu-l-Ile & [34] \\ Lichenysin G & FA-\(\beta\)-OH-l-Gln-l-L-[A\({}_{2}\)]-d-Leu-l-[A\({}_{4}\)]-L-Asp-d-Leu-l-[A\({}_{7}\)] & [6] \\  & A\({}_{2}\) = Leu/Ile, A\({}_{4}\) = Val/Ile, A\({}_{7}\) = Ile/Val \\ Surfactant BL86 & FA-\(\beta\)-OH-l-Glx-L-Leu-d-Leu-l-Val-l-Ass-d-Leu-l-[A\({}_{7}\)] & [35] \\  & A\({}_{7}\) = Ile/Val \\ Pumilacidin & FA-\(\beta\)-OH-l-Glu-l-Leu-d-Leu-l-Leu-l-Asp-d-Leu-l-[A\({}_{7}\)] & [36] \\  & A\({}_{7}\) = Ile/Val \\
**Fengycin family** & & \\ Fengycin & FA-\(\beta\)-OH & [37] \\  & -l-Glu-d-Om-d-Tyr-d-\(a\)Thr-l-Glu-d-[A\({}_{6}\)]-l-Pro-l-Gln-l-Tyr-l-Ile \\  & A\({}_{6}\) = Ala/Val \\ Plipastatin & FA-\(\beta\)-OH & [37] \\  & -l-Glu-D-Om-l-Tyr-D-\(a\)Thr-l-Glu-D-[A\({}_{6}\)]-l-Pro-l-Gln-D-Tyr-l-Ile \\  & A\({}_{6}\) = Ala/Val \\
**[PERSON] family** & & \\ Iturin A & FA-\(\beta\)-NH\({}_{2}\)-LAsn-d-Tyr-d-Asn-l-Gln-l-Pro-d-Asn-l-Ser & [38] \\ Iturin C & FA-\(\beta\)-NH\({}_{2}\)-LAsp-d-Tyr-d-Asn-l-Gln-l-Pro-d-Asn-l-Ser & [37] \\ Bacillomycin L & FA-\(\beta\)-NH\({}_{2}\)-LAsn-d-Tyr-d-Asn-l-Ser-l-Glu-d-Ser-l-Thr & [39] \\ Bacillomycin D & FA-\(\beta\)-NH\({}_{2}\)-LAsn-d-Tyr-d-Asn-l-Pro-l-Glu-d-Ser-l-Thr & [37] \\ Bacillomycin F & FA-\(\beta\)-NH\({}_{2}\)-LAsn-d-Tyr-d-Asn-l-Gln-l-Pro-d-Asn-l-Thr & [37] \\ Mycosubtilin & FA-\(\beta\)-NH\({}_{2}\)-LAsn-d-Tyr-d-Asn-l-Gln-l-Pro-d-Ser-l-Asn & [40] \\
**Other** & & \\ Antiadhesin & FA-\(\beta\)-OH-l-Asp-l-Leu-l-Leu-l-Val-l-Val-l-Glu-l-Leu & [41] \\ Bamylocin A & FA-\(\beta\)-OH-x-Glu-x-Leu-x-Met-x-Leu-x-Pro-x-Leu-x-Leu & [42] \\ Circulocin 1 & \(g\)FA-\(\beta\)-OH-x-Thr-x-Phe-x-Ile-x-Dba-x-Asp & [43] \\ Circulocin 3 & \(g\)FA-\(\beta\)-OH-x-Thr-x-Leu-x-Ile-x-Thr-Asn-x-Ala & [43] \\ Fusaricidin & \(g\)FA-\(\beta\)-OH-l-Thr-d-Val-l-Tyr-d-\(a\)Thr-d-Asn-d-Ala & [44] \\ Kurstakins & FA-x-Thr-x-Gly-x-Ala-x-Ser-x-His-x-Gln-x-Gln & [45] \\ \hline \end{tabular}
\end{table}