Figure 2.

Procedures for library screening. Genetic libraries, generated via methods depicted in Figure 1, have to be analyzed in order to identify improved protein variants employing methods, which depend on the individual protein case and the screen available. As such, the library can be expressed in a heterologous host and analyzed in vitro, here exemplified by a screen in multiwell format (A). If screening in vivo in a nonphotosynthetic heterologous host, fitness or survival of the mutant strains (B) or a colorimetric detection of improved mutants (C) can be utilized. These two approaches can also be employed in the photosynthetic hosts (D and E).