Bacterial aminophenylpyrrole-derived alkaloids (APPAs) represent high value lead compounds. Pyrrolnitrin, which was developed into globally important fungicides, is the only reported APPA produced by Proteobacteria. Recently, various APPAs showing diverse bioactivities were discovered from Bacteroidetes. Here, a bioinformatics and phylogenetic approach enabled the elucidation of the biosynthesis of the highly diverse APPAs in Cytophagales bacteria and their chemical diversification strategy. The biosynthetic gene clusters were identified in producer strains, and the biosynthesis was experimentally validated by heterologous expression experiments in E. coli. First, one enzyme-dependent biosynthetic step yields the tryptophan-derived precursor 3-(2′-aminophenyl)-pyrrole. Second, a spontaneous Pictet–Spengler-like coupling reaction enables the bacterial producer strains to create a libr...

The microbiome of three different sites at the Peruvian Pacific coast was analyzed, revealing a lower bacterial biodiversity at Isla Foca than at Paracas and Manglares, with 89 bacterial genera identified, as compared to 195 and 173 genera, respectively. Only 47 of the bacterial genera identified were common to all three sites. In order to obtain promising strains for the putative production of novel antimicrobials, predatory bacteria were isolated from these sampling sites, using two different bait organisms. Even though the proportion of predatory bacteria was only around 0.5% in the here investigated environmental microbiomes, by this approach in total 138 bacterial strains were isolated as axenic culture. 25% of strains showed antibacterial activity, thereby nine revealed activity against clinically relevant methicillin resistant Staphylococcus aureus (MRSA) and three against enteroh...