Desferrioxamines E (1), D2 (2), X1 (3), and X2 (4), four macrocyclic N-hydroxy-N-succinyl diamine-based siderophores, were produced efficiently by heterologous expression of a fusion biosynthetic gene cluster. This expression system consisted of three genes (mbsA-C) from marine metagenomic DNA and one gene (dfoC(C)) from the terrestrial bacterium Erwinia amylovora. The first three genes are functional in the production of the common monomers N-hydroxy-N-succinyl cadaverine (5, HSC) and N-hydroxy-N-succinyl putrescine (6, HSP), whereas dfoC(C) catalyzes the oligomerization and the macrocyclization reactions of compounds 5 and 6 to form compounds 1-4. This fusion gene cluster system provides a convenient expression platform for various biosynthetic genes of HSC-HSP based siderophores by simply switching the fourth gene by the cassette process.