Generally, Escherichia coli TOP10 cells are used for cloning. They are derivatives of the non-pathogenic K-12 laboratory strains. In our lab, DH5alpha is used. The detailed information of the E. coli mutations can be found in E.coli wiki. The likelihood of a human getting ill from working with these bacteria is therefore low. The most probable route of transmission would occur by accidental aerosol formation or ingestion. The Environmental Protection Agency states that the K-12 strain (which both DH5-Alpha and JM109 are derivatives of) is poorly retained in the human gut, so the chance of it becoming pathogenic by mutations is low[1]. Mainly for these reasons, this organism is classified as Bio-Safety Level 1.

Aspergillus niger N593, and 872.11 are all derivatives of N400, which is the sequenced CBS strain. They are non-pathogenic industrial workhorses. Additionally, the N593 and 872.11 have the pyrA auxotrophy marker. (see Fungi-related safety).

Public safety

In case of the accidental release of bacteria containing our BioBrick system, the physical conditions outside the lab are harsh to the E. coli strain chassis that are used, so the bacteria would be unable to grow and the DNA of the BioBrick system will not be widely. By means of natural genetic transformation the DNA of the BioBrick system could be taken up by other bacteria.

Additionally, as expression of the plasmid would incur a significant metabolic burden on a (probably non-pathogenic) soil bacterium, and do little to increase its fitness, it is considered unlikely that the plasmid would be propagated. Unfortunately it is not possible to know in advance what the actual effect of a natural transformation would be, but the odds seem to be in favour of it to cause little impact on the public and environment.