Based on Hans Blumenberg’s philosophical concept of »reoccupation«, the study analyzes why the microbe has never really been situated in the world, demarcating ontological shifts in modeling microbes. The shifts are related to techniques such as sequencing and digitizing, to microbe banks acting as world models, and to metaphysical vacancies co-created. These can be operated on a historiographic level, as highlighted by the world formula of bacterial photosynthesis. It allowed for imaginations of the Early Earth and an Iron-Sulfur-World. In sum, collecting and cultivating are shown to be crucial pre-operations for operative bio-ontologies, exemplified by a case study on the German Collection of Microorganisms (DSMZ).