Physical and Genetic Containment of Transgenic Bacteria for Real World Applications

Abstract

Synthetic biology has promised and delivered on an impressive array of applications based on genetically modified microorganisms. While novel biotechnology offers undoubted benefits, it comes with an attached risk of both known and unknown negative consequences, particularly if transgenic organisms are allowed to proliferate freely. To achieve containment of an organism, confidence to a near scientific certainty must be shown that they cannot transfer their transgenic genes to other organisms and that they cannot survive to propagate in unintended environments. This thesis develops novel ways to achieve the required containment for the application of microbes in an uncontrolled environment. A recoding scheme is developed for altering codon assignment, creating a genetic firewall between an engineered and a wild-type organism that prevents horizontal gene transfer. Toxin-antitoxin based kill switches that respond to environmental signals such as temperature and pH allow for control over the location a transgenic microbe can survive in. These technological advances are put in the context of the wider field of containment, and what regulation would be required to consider a transgenic microbe safe to deploy is discussed.