Fractional factorial approach combining 4 Escherichia coli strains, 3 culture media, 3 expression temperatures and 5 N-terminal fusion tags for screening the soluble expression of recombinant proteins.

Producing recombinant proteins in Escherichia coli (E. coli) is generally performed using a trial and error approach with the different expression variables being tested independently from each other. As a consequence, variable interactions are lost which makes the trial and error approach quite time-consuming.