In this study, we report a series of new microginins from a M. aeruginosa strain that can be summarized as non-halogenated, monoand di-chlorinated versions of Ada-Pro/mPro-Hphe/Htyr-Pro-(Tyr) scaffolds. The discovery of these new microginin congeners was motivated by genome mining of the producing strain, which had revealed the presence of a putative mic BGC predicted to encode microginins with a novel amino acid composition. We show that all core biosynthetic mic genes are functional in E. coli and confirm experimentally that these are, as previously postulated, responsible for the production of microginins. The heterologous expression of these compounds in E. coli opens the door for engineering variants for bioactivity screening, for example by domain substitution. In addition, it enables the straightforward discovery of additional natural microginin congeners from mic BGCs found in genome or metagenome data. Such strategies, which take advantage of the vast amount of BGC sequence data available, can prove useful for the discovery of novel, naturally-evolved variants of bioactive compounds, with improved biological activity or resistance properties, as recently illustrated by Brady and co-workers.