<p>This article traces the history of microbial culture collections to explore the evolution of microbial biodiversity conservation and biotechnological valorization between 1972 and 2022. It shows how a progressive assetization of microbial value led to an enclosure of the global microbial commons. Culture collections were enablers and victims of this change. Analyzing collections across Europe, the Americas, and Asia as well as the World Federation of Culture Collections (WFCC), the article reconstructs how culture collections functioned as a key infrastructure for the globalized take-off of the biotechnology industry. Biotechnological investment in microbial exploitation created important revenue streams amidst public funding cuts and collections’ declining role as research hubs. However, pressure to control and generate income from microbial assets also shifted moral economies governing microbial exchange and led to commercial rivalry between collections. While biodiversity concerns prompted a reconceptualization of collections as microbial arks, the 1993 Convention on Biological Diversity’s recognition of national sovereignty over bioresources further complicated microbial conservation. Actors such as the WFCC and Organisation for Economic Co-operation and Development (OECD) tried to reconcile access and benefit sharing (ABS) obligations and intellectual property (IP) via guidelines, networking, and accreditation. However, entrenched asymmetries in the global distribution of <i>ex situ</i> conservation infrastructures and microbial value generation remained unaddressed despite passage of the 2010 Nagoya protocol on ABS. Meanwhile, advances in sequencing and synthetic biology not only highlighted biases in existing collections, but also pointed to an era in which in silico approaches to biodiversity might supersede existing in vitro museums.</p>