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The majority of nonribosomal peptide synthases and type I polyketide synthases are multimodular megasynthases of oligopeptide and polyketide secondary metabolites, respectively. Owing to their multimodular architecture, they synthesize their metabolites in assembly line logic. The ongoing genomic revolution together with the application of computational tools has provided the opportunity to mine the various genomes for these enzymes and identify those organisms that produce many oligopeptide and polyketide metabolites. In addition, scientists have started to comprehend the molecular mechanisms of megasynthase evolution, by duplication, recombination, point mutation and module skipping. This knowledge and computational analyses have been implemented towards predicting the specificity of these megasynthases and the structure of their end products. It is an exciting field, both for gaining deeper insight into their basic molecular mechanisms and exploiting them biotechnologically.

Iron is an essential nutrient for almost all bacteria; however, at neutral pH its bioavailability is limited. Siderophores are iron-binding compounds of low molecular weight that enable the microorganisms that produce them to obtain the necessary iron from the environment. Fluorescent pseudomonads include those that are plant growth promoting, human and plant pathogens, as well as bacteria involved in the biodegradation of xenobiotics. Although pyoverdine is the main siderophore produced by different fluorescent pseudomonads, other siderophores produced by fluorescent pseudomonads include pyochelin, (thio)quinolobactin and pyridine-2, 6-bis thiocarboxylic acid. Research on siderophores continues to reveal new information on their regulation, biosynthesis, function and properties. In this review, we focus on recent advances in the field, particularly on newly characterized siderophores produced by fluorescent pseudomonads and their biotechnological potential.