Synthetic microbiology is among the most promising approaches for getting more at lower cost and in the respect of the environment. Directed evolution is recognized as a key approach to obtain biobricks for synthetic biology. In this context there is a considerable interest in the development of continuous systems for directed evolution of biomolecules based on “orthogonal” evolution vector on which accumulation of mutations can be uncoupled from accumulation of mutations on the host genome. This project aims at developing such a system for the gram-positive bacterium Bacillus subtilis. An important step towards biotechnological applications will also be made by using the proposed system for: the evolution of new transcription factors for genetic circuit engineering in B. subtilis; and the evolution of new proteins binding inorganic ions such as heavy metals that might serve as biosensors and in bioextraction systems. The work program decomposes into three work-packages : development of a system for directed evolution in B. subtilis ; in silico analyses for the optimization of the system ; application to biobrick production. B. subtilis is a totally harmless bacterium of considerable biotechnological interest: it stands as the second model bacterium after Escherichia coli and is as such a natural chassis for synthetic biology; it is also a soil dweller (and probably a normal gut commensal in humans) with highly diverse physiological capabilities, and an ability to survive extreme conditions in the form of spores. B. subtilis and several of its close relatives of the Bacillus genus (notably B. licheniformis and B. amyloliquefaciens) exhibit a remarkable capacity of biological compound production that can be scaled-up to industrial levels are widely used in the industry for enzyme production.