## 2 Results  
In this work we investigated the biosynthetic potential of the _Paenibacillus polymyxa_ strain DSM 32871. Its product pattern was compared with that of the well characterized M1 strain [10; 11], which was implemented as a model strain. To explore the antimicrobial capacity of these strains we investigated their biosynthetic products by MALDI-TOF mass spectrometry in a time and space dependent fashion. We focused on two lipopeptide complexes, the fusaricidins and the polymyxins, as well as their volatiles which facilitate long-range interactions with plants and their native microbiota in the rhizosphere. For this purpose, DSM 32871 and M1 were grown in various cultivation media (Landy, LOP, LB, TSA and GSC). Samples were taken at growth times of 12; 24; 48; 72 and 96 h to investigate the time profile of the production of the tested bioactive compounds and to determine their specific location. It was assessed whether they were residing in the cell or at the outer cell wall, or if they were released into the cultivation media. Figure 1 shows MALDI-TOF mass spectra of surface extracts (Figure 1A,C) and culture filtrates (Figure 1B,D) of DSM 32871 and M1 in the mass range of 800-2000 Da indicating three lipopeptide complexes, the fusaricidins, polymyxins and tridecaptins. The strains were cultivated in the LOP medium. Surface extracts were prepared by extraction of cell material obtained from agar plates with 50% ACN/0.1% TFA. Fusaricidins and tridecaptins preferentially were found attached to the outer surface of the _Paenibacillus_ strains, while the polymyxins were mainly released into the cultivation media. At growth times higher than 48 h fusaricidins were also enriched in the culture filtrates. In particular, the fusaricidin complex is distinguished by an unusually high variability [11]. Its composition depends on the growth medium as is apparent from Supplementary Materials (Figure S1) for cultivation of DSM 32871 and M1 in the Landy/LOP and LB medium. Interestingly, for DSM 32871 grown in the Landy or LOP medium in the MALDI-TOF mass spectra (Figures S1A and 2A), fusaricidins A and B with molecular masses of \(m/z=883.9\) and 897.9 and their derivatives at \(m/z=954.9\) and 968.9 differing from the parent ions by a mass difference of 71 Da were prevalent, while for DSM 32871 grown in the The culture filtrate of DSM 32871 grown for 48 h in the LOP medium (Figure 2A) was fractionated by reversed phase HPLC on a 300 SB-C8 Zorbax column. The chromatogram in Figure 2B shows product fractionation in fractions 20 to 30. MALDI-TOF mass spectra of aliquots of fractions 22-30 is shown in Supplementary Materials (Figure S2A-K) demonstrating the separation of the produced compounds. Fusaricidins are the main products of DSM 32871. They were distributed among a broad range in fractions 22-30. Polymyxins appeared in fractions 22 and 23. Tridecaptins were found in fractions 28-30. The fusaricidins produced by _P. polymyxa_ DSM 32871 are summarized in Table 1. They comprise the well-known fusaricidins A-F [5; 6; 10; 11]. In addition, fusaricidins were found at \(m/z\) = 869.53 and 855.51 which could be derived from fusaricidin A either by substitution of Thr (1) or both threonines in positions 1 and 4 by series, respectively. Apparently, three series of new fusaricidin species were detected. For DSM 32871 the occurrence of derivatives of all these fusaricidins was characteristic, which differ from their parent ions by a mass difference of 71 Da indicating modification by attachment of an alanine residue. These variants were among the dominating species in the mass spectra of DSM 32871. In addition, for this strain two other yet unknown fusaricidins with molecular masses of  
Figure 1: MALDI-TOF mass spectra of surface extracts of _P. polymyxa_ DSM 32871 (**A**) and M1 (**B**) after growth for 72 h on Landy agar plates and in the culture filtrates after growing these strains in the LOP medium (**C**,**D**) in the mass range of \(m/z\) = 800–2000 Da.