https://www.sciencedaily.com/releases/2019/04/190401171343.htm

C. ethensis-2.0 is based on the genome of a well-studied and harmless freshwater bacterium, Caulobacter crescentus, which is a naturally occurring bacterium found in spring water, rivers and lakes around the globe. It does not cause any diseases. C. crescentus is also a model organism commonly used in research laboratories to study the life of bacteria. The genome of this bacterium contains 4,000 genes. Scientists previously demonstrated that only about 680 of these genes are crucial to the survival of the species in the lab. Bacteria with this minimal genome are viable under laboratory conditions.

Beat Christen, Professor of Experimental Systems Biology at ETH Zurich, and his brother, Matthias Christen, a chemist at ETH Zurich, took the minimal genome of C. crescentus as a starting point. They set out to chemically synthesise this genome from scratch, as a continuous ring-shaped chromosome. Such a task was previously seen as a true tour de force: The chemically synthesised bacterial genome presented eleven years ago by the American genetics pioneer Craig Venter was the result of ten years of work by 20 scientists, according to media reports. The cost of the project is said to have totalled 40 million dollars.