The present invention relates to a recombinant host cell, comprising in its genome preferably heterologous gene expression cassettes capable of being expressed in the host cell, the gene expression cassettes encoding a nucleic acid sequence encompassing at least 80% of the full-length sequence of the mamAB operon, the mamGDFC operon, and the tmms6 operon of a magnetotactic alphaproteobacterium, respectively, and preferably further comprising gene expression cassettes capable of being expressed in the host cell, the gene expression cassettes encoding a nucleic acid sequence encompassing at least 80% of the full-length sequence of the mamXY operon and/or the feoAB1 operon of a magnetotactic alphaproteobacterium wherein the recombinant host cell, upon expression of the gene expression cassettes in their entirety, is capable of producing magnetic nanoparticles. Preferably, the recombinant host cell is derived from Rhodospirillum rubrum. Furthermore, the present invention also relates to a corresponding method for producing such recombinant host cell by means of genetic transposition.
