While beneficial applications exist, GMMs may pose unique, long-term risks to human and environmental health due to their biologically active, self-replicating nature and capacity for mutation and dispersal. Current regulatory frameworks remain fragmented, with no coordinated international policy.

This review highlights key risks, including horizontal gene transfer, disruption of human microbiomes, and the emergence of “super bugs” or impacts on soil carbon cycles. Engineered microbial enzymes may also contribute to autoimmunity.

Given limited understanding of microbial ecology, the authors propose a biosafety workflow with pre-release risk assessment and post-release monitoring, and call for stronger use of the precautionary principle in regulation.

This review examines emerging trends in the governance and policy landscape for real-world deployment of genetically engineered microbes (GEMs) in the United States and Europe. A recent wave of commercialized GEMs in the US suggests renewed interest in open release after decades of low activity, with applications spanning agriculture, environmental restoration, energy, and health.

These developments challenge existing governance frameworks in several ways. The feasibility of strict product- or process-based regulation is increasingly tested, while the long-term persistence and ecological action of GEMs complicate traditional risk assessment approaches. Synergistic and indirect impacts are difficult to predict, requiring methods that can address high levels of uncertainty.

At the same time, diverse applications and new business models—such as direct-to-consumer approaches—raise concerns around stewardship, consent, transborder movement, and monitoring. Addressing these issues will require interdisciplinary research and broader stakeholder deliberation to support more robust and adaptable governance.